SAN FRANCISCO — Billionaire opponents of California’s proposed wealth tax have spent more fighting it than they ever have on a political cause in the state, according to a POLITICO analysis.

A record $612 million from more than 70 current and former California billionaires is flooding this year’s state elections, nearly half of it for groups working to defeat Proposition 40, the wealth tax initiative on Tuesday’s ballot, POLITICO found.

The fight over Prop 40 has brought California’s wealthiest residents — many from its native tech industry — together in an unprecedented show of political coordination, the new data reveals. Tech leaders say the wealth tax has accelerated plans for broader political engagement this cycle, building networks that could be the foundation for future campaigns.

It’s a particularly striking display of unity from Silicon Valley’s notoriously hard-to-organize donor class. Google co-founder Sergey Brin is by far the well-funded opposition’s biggest benefactor, with former Google CEO Eric Schmidt, venture capitalist John Doerr, Stripe CEO Patrick Collison and crypto executive Chris Larsen also among those who have contributed the most dollars in trying to stop the billionaire tax.

The possibility of a tax on their assets has drawn more than $293 million from at least 30 California billionaires, the majority of whom made their fortunes in tech but otherwise span industries, from agriculture to real estate — as well as the political spectrum, from established Democratic megadonors to some Republican allies and first-time donors.

Frank Slootman, the billionaire board chair and former CEO of cloud data company Snowflake, said he only had a “moderate” interest in politics despite giving $5 million to an anti-Prop 40 group, arguing that the measure erodes private property rights and the state’s economic dynamism.

“This upends the most basic assumptions we have about being a taxpayer and a resident of a state,” said Slootman, who has no prior record of California campaign contributions. “I vote in most elections, that’s about it. This is not about politics for me — it is far more important than that.”

The other half of billionaires’ spending this year came largely from Tom Steyer, a rare billionaire endorser of Prop 40 who bankrolled his own failed gubernatorial bid — the most expensive primary campaign in state history.

Even longtime strategists who have worked for statewide candidates and California’s costly ballot battles struggled to find a historical parallel for the coordination or scale of billionaire spending against Prop 40.

Rob Stutzman, a Sacramento political consultant whose past campaigns have involved a billionaire gubernatorial candidate and record-breaking ballot spending over sports betting, said that Silicon Valley leaders see Prop 40 as an “existential threat to tech in California” and the innovation that has taken root in the region for decades.

“Having to defend against a direct assault is a more unifying principle,” Stutzman told POLITICO. “They’re known for their pet issues that are harder to organize their peers around, but you can circle the wagons to protect yourselves. There is nothing that focuses similar-situated people.”

Proponents of Prop 40 contend the measure is necessary to backfill federal health care cuts.

The last year billionaires in California came closest to spending at this level was 2010, when they dropped $147 million on state races and measures, according to POLITICO’s analysis — a total that’s just over half of what the current wealth tax proposal mobilized. Most of it was the result of billionaire Meg Whitman, a former CEO of eBay and Hewlett-Packard, self-funding her unsuccessful Republican campaign for governor.

Scott Ellis, a millionaire and Prop 40 supporter who formerly served as a senior director at HP, described the magnitude of billionaire spending to fend off the measure as “a completely different animal” than past examples of “a lot of money spent by a rich person to get themselves elected.”

“People with wealth and extreme wealth are getting much more brazen than they used to be,” Ellis told POLITICO. “These people have tremendous resources. They have an incredible range of choices to make, including choosing to oppose this kind of ballot measure.”

Representatives for several billionaire opponents of Prop 40, including Schmidt, Larsen and agricultural titan Stewart Resnick, declined to comment on POLITICO’s findings.

Others, like Doerr, referred POLITICO to Building a Better California, a new Brin-led political operation that has become the primary vehicle for billionaire money against Prop 40.

The group defended the importance of its cause, arguing the measure would “permanently devastate” the state tax base and budget while undermining the health care funding it’s intended to patch.

“We are fortunate to be supported by entrepreneurs and business leaders who have built their businesses and created hundreds of thousands of jobs here, and who share a deep commitment to advancing policies that will improve quality of life for all and protect the state’s economic, jobs, and innovation engine for generations to come,” Building a Better California spokesperson Abby Lunardini said in a statement.

Debru Carthan, vice president of the SEIU-United Healthcare Workers West union behind the billionaire tax, responded to the contributions, saying, “no amount of billionaire spending is going to intimidate us or turn us back.”

A reawakening

Tech leaders have told POLITICO that the wealth tax awakened a sleeping giant in California politics: their previously disengaged industry peers, who months ago suddenly started spending across the ballot to steer California in a more moderate, business-friendly direction. The threat injected the wider political organizing, some of which preceded the measure’s introduction, with a new sense of urgency.

“The tech community has wanted to become a bigger player in California politics,” said veteran Democratic strategist Steven Maviglio.

“They’re building an infrastructure, I think, for the long term because they’ve become a dominant player in our economy, and they now, after literally a decade of being hands-off, want to be very involved because they see the consequences,” Maviglio, who is working on a separate housing and environment-related ballot fight where Schmidt’s wife, Wendy Schmidt, has given $10 million, told POLITICO.

Earlier efforts to unify faltered amid strategic disagreements and overinflated fundraising promises. That was especially apparent in the push to rally Silicon Valley around San Jose Mayor Matt Mahan, a business-friendly candidate with a background in startups, during the California gubernatorial primary.

Although Building a Better California wasn’t spared its share of donor turmoil, an initial patchwork of opposition efforts eventually consolidated resources under the Brin operation’s strategy, devised with the help of veteran ballot-measure consultant Ned Wigglesworth.

The group also brought on fundraisers associated with California Gov. Gavin Newsom’s inner circle. Newsom has publicly opposed imposing a billionaire tax at the state level.

In addition to funding Prop 40 attacks, several billionaires claimed to have fled the state to avoid the tax. Brin, for example, registered to vote in Nevada. Because the one-time, 5% tax on assets would apply to billionaires who lived in the state as of Jan. 1, 2026, POLITICO’s analysis covers billionaires with recent California ties, based on information from Forbes, the progressive nonprofit Americans for Tax Fairness and news reports.

Some of those billionaires made their moves quietly, highlighting a split over how they should respond to the possibility of the tax passing.

“This has been a point of friction between me and some of my other billionaire friends,” Palmer Luckey, the billionaire founder of defense tech giant Anduril, said on a call with reporters this week. “They’ve said things like, ‘Palmer, you have to have solidarity for us. You can’t enable these really bad policies. If you stay and if you don’t leave, it’s going to show them that there’s no consequences.’”

Luckey, a vocal critic of the tax who hasn’t donated to the opposition campaign, added, “I’m planning on staying in California. I’m going to keep fighting it. I’m hoping that this doesn’t pass.”

Meta revealed a plan last week incentivizing CEO Mark Zuckerberg to stay near the company’s Silicon Valley headquarters after the longtime California resident told a special committee of his board he was considering leaving over the tax. He also hasn’t challenged Prop 40 through political contributions.

DoorDash CEO Tony Xu, who poured almost $3.5 million into trying to prevent the wealth tax, was one of three members on the special committee negotiating with Zuckerberg.

Behind the money

Brin is single-handedly putting $102 million behind Building a Better California as it campaigns to sink Prop 40. This year, he’s also backed unsuccessful runs by Republican Chad Bianco and the moderate Mahan in the gubernatorial primary, plus Republican Steve Hilton’s campaign for governor. Federally, he’s given close to $450,000 to the Republican National Committee.

But before this cycle, Brin had been a sporadic donor, gone dark for many years. His last disclosed political donation in California was in 2010 — for $200,000 to join other Silicon Valley leaders in opposing an ultimately defeated ballot measure that would’ve suspended a state climate law.

Some of the billionaire donors — Slootman, Roblox CEO David Baszucki, Robinhood co-founders Baiju Bhatt and Vlad Tenev, Figma CEO Dylan Field, fintech executive Max Levchin and software founder Andrew Karam — have no history of spending on California politics before this year, according to state campaign records.

Tenev said in a statement that he donated to Building a Better California to support one of two other measures the group has advanced, which is designed to invalidate Prop 40 and would prohibit new taxes on various forms of personal savings.

“Special taxes on retirement and unrealized investment gains run contrary to the intent of the investment vehicles that have helped millions of Americans build wealth for the long term,” the Robinhood chief executive said. “History shows us that taxes aimed at a few have often been extended permanently to include more taxpayers over time.”

Another Building a Better California donor, Doerr, on the other hand, was a pioneer in shaping how Silicon Valley engaged with politics and Washington. He co-founded TechNet in 1997, which launched a political action committee as a key part of its strategy. Today, the influential industry trade association manages both federal and state-level PACs on top of a vast bipartisan lobbying network, with Google, Stripe and Kleiner Perkins among its many corporate members.

The wealth tax has also brought former Sequoia venture capitalists, Michael Moritz and Doug Leone, onto the same side after they previously diverged on California’s partisan redistricting fight at the ballot last year. They spent $7.5 million and $100,000, respectively, on groups fighting Prop 40.

Leone is a prolific Republican donor who re-endorsed President Donald Trump in 2024, while Moritz has consistently criticized Trump and chided his supporters in Silicon Valley for making a mistake.

No less than a dozen of the billionaires spending on groups that oppose Prop 40 are current CEOs — including DoorDash’s Xu, Roblox’s Baszucki, Robinhood’s Tenev, Stripe’s Collison, Affirm’s Levchin, Schmidt of rocketmaker Relativity Space, Hemant Taneja of top venture capital firm General Catalyst, Field of design platform Figma and Parker Conrad of HR software provider Rippling.

Collectively, they’ve plowed at least $88 million into their cause.

Several more of the billionaires in POLITICO’s analysis chair influential companies and firms. The opposition effort has received $40 million from Doerr, the Kleiner Perkins venture capitalist; $17.5 million from Larsen at the crypto company Ripple; and $2 million from George Marcus at the Bay Area real estate titan Marcus & Millichap — to name a few.

Will they come together again?

Whether the campaign infrastructure built by billionaires and the tech industry for the midterms will endure is still an open question.

Other new tech-funded groups this cycle have promised to play the long game and framed their plans around at least a decadelong horizon. Building a Better California itself has also committed to sticking around for the foreseeable future.

California political observers point to the size of the Brin-backed operation, as well as its decision to focus on additional environmental and housing measures, in predicting it won’t stop after the election.

Still, the unprecedented nature of their mobilization raises questions about what cause would be able to activate so many of these individuals again. Donors and advisers to Building a Better California previously clashed over whether spending on non-wealth-tax issues, such as environmental policy, could jeopardize the group’s success.

In the past, “if you look at those big dollar campaigns, ballot measure campaigns, those were funded in general by an industry,” said Jim Ross, a Bay Area-based Democratic consultant. “Wherein this, it’s a bunch of individuals, very wealthy individuals, but they don’t necessarily have any commonality other than they don’t want to be taxed.”

“When you have a group of wealthy people all putting money into this, a lot of the challenge is going to always be: How do you manage that coalition? How do you keep everybody moving in the same direction?” he added.

One ready answer is a revived wealth tax effort.

Last week, Rippling CEO Conrad said in a social media exchange with Silicon Valley Rep. Ro Khanna, whose early support for the wealth tax alienated some of his original tech backers, that he “absolutely cannot afford to stay” in California — reasoning the measure may soon be followed by another one-time tax in the next election.

Slootman made a similar calculation.

“In a one-party state with super majorities in both chambers, we are at risk for everything we own,” he said. “We are hunted animals in this state. They will be at it again in two years.”

Rosmery Izaguirre contributed to this report.

About this analysis

POLITICO’s analysis compiled records from the California secretary of state for 142 California billionaires that have contributed to state campaign committees, including 30 who had given to the following committees opposing Proposition 40: Building a Better California, Californians Against Tax Increases and Golden State Promise. Reporters reviewed donation records to verify names and employers matched with the billionaires who live in the state, as well as contacted each donor. Donations are as of Oct. 26.

Forbes estimated the wealth of the persons included in this analysis. Because billionaires often own properties in multiple states, we relied on Forbes to identify each person’s residence and supplemented with further data provided by the progressive nonprofit Americans for Tax Fairness. We included people who have recently left the state, including cases when they said they were leaving to avoid the potential wealth tax.

General Compute is betting on inference chips from outside the Nvidia ecosystem.

Mark Carney’s pursuit of a global alliance of middle powers has a Europe problem.

Canada’s prime minister wants to help build a new world order that can counterbalance the power of the United States and China. But his vision depends on a new relationship with a Europe that doesn’t see itself as a middle power at all. 

European Commission President Ursula von der Leyen has a different vision: a Brussels-centered bloc that extends the EU’s economic and geopolitical influence, starting with Canada. The idea, according to senior European lawmaker Siegfried Mureșan, is to create an opportunity for the EU to become the “global center of gravity for liberal democracies.” 

The competing visions will be tested this week when Carney and von der Leyen meet in Montreal for a summit intended to chart a new course for transatlantic relations. Both want to demonstrate they can prosper in a world upended by U.S. President Donald Trump. But they have different ideas about their curious new alliance — and face political resistance that could limit how far the partnership can go. 

Von der Leyen’s offer of “associate membership” in the EU surprised officials on both sides of the Atlantic. Four diplomats told POLITICO they were not consulted before she floated the idea in the State of the Union. The officials added that they don’t understand the label, which has yet to be defined. Germany has since led pushback on the plan.

“We’ve definitely put the cart before the horse,” one of the diplomats said. “We’re announcing something and then figuring out how to flesh it out.”

Trump called the membership idea “laughable,” but also threatened “very serious tariffs” should it come to be — a reminder that leaders in pursuit of Washington workarounds must avoid provoking the White House. 

The leaders are under pressure to leave Montreal with more than a liberal democratic photo-op. For starters, they need to decide what “associate membership” means — and disarm resistance in the EU capitals blindsided by von der Leyen’s plan.

Canada’s Ambassador to the EU Jonathan Wilkinson told POLITICO last month that people got too hung up on a label that was revealed prematurely. Carney called the Canada-EU relationship an “alliance for the future” when he addressed European lawmakers in Strasbourg.

Wilkinson said the Canada-EU project will show other democratic nations how to deepen partnerships. “It ties into very much what [Carney] talked about at Davos — and after Davos.”

Carney, von der Leyen and European Council President António Costa have two days to chart what’s next while American foreign policy continues to stress test geopolitical relationships in midterm campaigns that will shape Trump’s last two years in office.

The economic divide 

Ottawa considers the EU an obvious partner in its push to diversify trade away from the U.S. There’s already a free-trade agreement that both sides view as being underutilized. 

Leaders gathering in Montreal this week will celebrate the 10th anniversary of the Canadian-EU trade agreement, nicknamed CETA. But nine EU member countries have yet to ratify the deal, underscoring the challenge of turning rhetoric into reality. 

“We have shared challenges and many more shared opportunities,” Canadian International Trade Minister Maninder Sidhu told reporters last week in Dublin, where he was invited to participate in an informal meeting of EU trade ministers, a preview of what a more integrated Canada could look like. “Canada wants to be Europe’s most reliable partner.”

Sidhu said CETA utilization rates in EU member countries range from 60% to 80%, making a point about room for improvement and perennial challenges. “We know there’s room to grow.”

Von der Leyen’s associate membership plan “has been coldly received by member states,” a senior EU official said. “It [the summit] is more about what we do, how we can use the real potential of the CETA agreement.” CETA has been provisionally in force since 2017.

Trade talks between Canada and the bloc read like a lengthy transatlantic grievance list.

At a meeting between Brussels and Ottawa last October, the EU complained about Canadian taxes it says disproportionately hit European carmakers, opaque cheese-import quotas, cumbersome rules on cosmetics and what it considers discriminatory provincial taxes and markups on European wines and spirits.

Canada, meanwhile, warned that the EU’s deforestation rules could burden its exporters, questioned the impact of Brussels’ carbon border tax and pressed for greater recognition of Canadian standards in areas including AI.

The senior EU official described the relationship as constrained by “irritants and unfulfilled promises” that must be resolved if the two sides are to make progress.

There are hurdles ahead. Even as Canada and the EU imagine a deeper economic and security partnership, both are pursuing industrial policies that could shut the other’s companies out of lucrative public contracts — death by compounded trade barriers.

Brussels has concerns about Ottawa’s “Buy Canadian” initiatives and their compatibility with the EU-Canada free trade agreement. “Some member states didn’t like the ‘Buy Canada’ thing from Carney,” the official added.

Canada is likewise uncertain whether its companies will qualify for the EU’s proposed “Made in Europe” preferences foreseen in a major industry bill that would seek to channel public procurement spending to European companies. The EU is divided over whether to extend those preferences to trusted trading partners, a topic that is expected to come up in Montreal.

Canadian business leaders recognize the domestic appeal of “Buy Canadian” in the face of Trump’s threats, but warn there will need to be concessions.

“It’s something that will have to be resolved in order to move the relationship deeper, particularly with respect to industrial cooperation or collaboration,” Mark Camilleri, president of the Canada EU Trade and Investment Association, told POLITICO.

Camilleri likened the 10-year-old CETA deal to a garden overgrown with weeds. “It pains me to see market access being eroded through Canadian and European preferences,” he said.

Pressure is on

European and Canadian leaders are under pressure to deliver wins this week that demonstrate that “non-hegemons” — a descriptor Carney used in his Davos speech — can survive and thrive in an age of great-power rivalry.

Canadians currently support closer ties with Europe. But the EU faces political headwinds of its own, from fraught budget negotiations within the bloc to right-wing populist movements that are picking up momentum in some of its biggest economies.

One likely deliverable is a new digital trade agreement. Talks launched in March and were still underway last week. But the agreement lacks substantive text on artificial intelligence, leaving the two sides to find other places to cooperate, potentially through the EU’s proposed Cloud and AI Development Act. That proposal seeks to reduce reliance on U.S. tech giants, raising the risk of a new row with Washington. 

The European Commission is also pushing for Canada to join Erasmus+, the bloc’s student exchange program, according to one EU official. Carney has already publicly expressed interest. 

But Brussels has bigger ambitions for the partnership. The EU is pressing Canada to increase its funding for Ukraine, a test of Canada’s willingness to take on more of the security burden. 

For von der Leyen, securing that commitment would be a win. So would leaving the summit with a pledge from Carney to explore her offer of an “associate membership” — or whatever they end up calling it.

Zi-Ann Lum reported from Toronto, Sebastian Starcevic from Brussels and Camille Gijs from Dublin.

The exposure was immense, with AI multiplying the risks — and yet time-tested global cybersecurity procedures appeared to be functioning. Then suddenly, it all broke down.        

The decision by a cybersecurity company on Wednesday to prematurely release information about a flaw in the popular PHP computer programming language left much of the web exposed to hackers, triggering a panic that brought to life months of warnings of how the AI-powered era could cause widespread damage.

The flaws in PHP, discovered using AI tools through a months-long process coordinated by OpenAI, caused cyber agencies across Europe, the U.S., the U.K., Australia and Canada to post urgent warnings Wednesday. Numerous governments took websites offline as a precaution.

While no major hacking damage was immediately apparent, the way the incident unfolded over 72 hours showed how easily cybersecurity processes can break down and the outsized consequences of cyber risks in the AI era.

The man who set off the chain reaction with the early release — Chainguard’s CEO Dan Lorenc — quickly apologized in a LinkedIn post. But on Thursday, in an interview with POLITICO, Lorenc said he’d shared the information ahead of time because the flaw was already being exploited. Though others disputed that, Lorenc said he believed he’d seen enough evidence to invalidate an embargo set up to allow time to find a fix for the flaws. 

While he disputed that his actions would have caused problems for other defenders, Lorenc conceded that the evidential threshold in these coordinated cyber defense systems is a “grey area.” 

The revelation of the PHP flaw brings out into the open what cyber officials have been bracing for since the arrival of the most powerful tools of artificial intelligence, which not only can be used to discover vulnerabilities but also to exploit them at scale. 

The cybersecurity world’s long-established protocols helped prevent disaster scenarios, in which hackers would have successfully exploited the vulnerabilities to take control of numerous websites and access their data. But now the scale and end-of-days potential of AI-driven cyber risks are visible for the world to see. 

This “is what happens when AI turns up a flaw that’s been hiding for years,” said Eylam Milner, co-founder and chief technology officer at cybersecurity start-up Echo. The vulnerabilities, he added, are “about as serious as it gets for the web.”

Origin story

Understanding how this week’s emergency unfolded offers a glimpse at how companies and authorities are working to stave off attacks — and how much risk they face going forward. 

The origins of the incident can be traced back as far as April when top frontier AI firm Anthropic unveiled Mythos, leading some in the cybersecurity world to worry that systems would quickly be overrun by advanced artificial intelligence, with potential for catastrophic events to ensue.

But while researchers did find more flaws in computer systems in the months after Anthropic and other AI firms like OpenAI released those models, they had little impact in the real world. Even the Hugging Face incident, a widely discussed hack that saw OpenAI’s autonomous AI agents go rogue during an internal security evaluation, related more to the level of control AI companies exert over their models than their power to break into systems worldwide. 

That changed this week after researchers unveiled the vulnerability in PHP, a coding language estimated to be integrated into some 70% of the web.

The process by which information about flaws is released among cybersecurity officials and affiliated companies is crucial. Through a longstanding practice known as coordinated disclosure, researchers and companies that identify flaws can find a fix and share it confidentially with agencies and others before releasing to the public, meaning they don’t hand malicious hackers the gift of a hole without a fix.

In the case of the PHP flaw, that process worked well, but not perfectly. Information about the bugs started to circulate ahead of the planned release time. Then, according to the PHP Foundation, Chainguard “unilaterally broke the embargo,” which “disregarded weeks of work by many parties toward a coordinated disclosure.” PHP Foundation executive director Elizabeth Barron told POLITICO by email that while it was “disappointed” with Chainguard, it hopes to “rebuild trust with them in the future to ensure we can continue to collaborate effectively.”

After the leak— which meant information about the bugs was in the open before the fix was ready — confusion quickly ensued, with government bodies and private companies choosing to temporarily shut down their websites rather than risk potentially damaging breaches to their data and the sites themselves.

Early Thursday, Matthew Prince, the CEO of Cloudflare, an internet services company that is widely used by websites to block cyberattacks, giving it a high level of visibility over what hackers are doing, said in a post on X that it had seen “millions” of attempts to exploit the flaw.

Cloudflare saw thousands in the 10 hours before the flaw was publicly announced, then tens of thousands in the 45 minutes after the announcement, hundreds of thousands within two hours, and now millions, Prince said.

Amazon’s cloud division also said the flaw is “now being broadly exploited in the wild.”

One senior U.S. government cyber official said that federal authorities have been overwhelmed — and not just by PHP. The same day the world was racing to address PHP, they were also dealing with bugs in node.js, a widely used JavaScript framework, Fortinet, GitHub and Oracle.

“The fire department is fighting multiple fires at once,” the official said, adding: “The good news is they’re all one-story structures on fire, which the fire department deals with all day, every day.”

More to come

Dauntingly, OpenAI said there’s more on the way. “These bugs are among several significant vulnerabilities we’ve already found and are working to fix, and we expect similar findings to increase sharply in the coming months,” the company said Wednesday in a statement.

Matthijs van Amelsfort, head of the Dutch cybersecurity agency, said in an interview that the job of keeping computer systems safe has been transformed by the advancement of AI. “As soon as the frontier models came out, that’s exactly what we said, this will be the trend,” he said. “And actually that’s happening now.”

Thomas Caspers, vice president of Germany’s cyber agency BSI, concurred: “We expect that [to be] happening more and more during the coming months.” 

AI also ramps up the risks once the flaws are out in the open. Cyber agencies’ recommendation that organizations take their websites offline was “really a drastic measure,” Caspers said. “We wouldn’t have done that a few years ago or so.” But because AI has made it quicker and easier to exploit flaws, “we had to do that,” he said. 

At the same time, the use of advanced AI to detect the flaws may create a new level of protection against malicious hackers looking to take advantage of them. Caspers said that though his German agency has also seen attacks, it has not seen any successful use of the flaw by hackers.

“It seems a little bit more complicated than expected to exploit,” he said. 

Despite the fact that AI offers a new way to discover flaws, the work involved in keeping systems protected is more quotidian, with cyber agencies urging organizations to install the fix shared by the PHP Foundation, in a process known as patching.

“There are three things that you have to do right now,” said van Amelsfort from the Dutch agency. “And that’s patch, patch, and patch.” 

John Sakellariadis contributed to this report.

Cyberattackers have made “millions” of attempts to take advantage of a critical hole in a building block of the internet, a key cybersecurity provider said early Thursday.

Two top European cyber officials later told POLITICO that hackers have so far struggled to exploit the vulnerability.

Cybersecurity agencies worldwide continue to scramble to respond to the public revelation Wednesday of a flaw in PHP, a foundational computer programming language used to underpin 70% of the internet. 

Matthew Prince, the CEO of Cloudflare, an internet services company that is widely used by websites to block cyberattacks — giving it a high level of visibility over what hackers are doing — said in a post on X that it’s seen “millions” of “attempts to exploit” the flaw.

Cloudfare saw thousands in the 10 hours before the flaw was publicly announced, meaning information must have leaked, then tens of thousands in the 45 minutes after the announcement, hundreds of thousands within two hours, and now millions, Prince said.

Amazon’s cloud division also said the flaw is “now being broadly exploited in the wild.”

But Thomas Caspers, vice president of Germany’s cyber agency BSI, said in an interview that though his agency has also seen attacks, it has not seen any successful use of the flaw by hackers. 

“It seems a little bit more complicated than expected to exploit,” he said. “When we had the planning process before the release of the patch, we were expecting a much faster track of the attackers.” 

Caspers is not certain why this is the case at this stage, but said it appears that successfully making use of the flaws is harder than expected. Global cyber officials were part of a process coordinated by OpenAI, to find and fix the flaws. “An ad hoc exploitation seems a little more difficult than expected,” he said.

The challenge for bad actors may also be linked to the major AI providers building guardrails so their tools can’t be used to exploit flaws, he said. When a POLITICO reporter as a test asked ChatGPT and Claude, models from OpenAI and Anthropic respectively, how to exploit the PHP vulnerabilities, both chatbots declined to provide the information. The two companies did not immediately respond to requests for comment. 

Numerous European government departments took their websites offline as a precaution to Wednesday’s developments. As of Thursday morning, key French websites such as the justice ministry and the data protection authority still featured a message they were undergoing maintenance. 

Matthijs van Amelsfort, the head of the Dutch cybersecurity agency, told POLITICO that his agency has no indication that the flaw is “actively being misused” but said that can change, particularly because AI makes it easier to exploit flaws. The agency took its website offline on Wednesday, but it is now back up.

This article has been updated.