By PYMNTS | October 21, 2026
Many websites around the world were taken down as a precaution or for preventative maintenance Wednesday (Oct. 21) as organizations responded to the disclosure of a widespread web vulnerability, according to multiple media reports.
As PYMNTS reported Wednesday, OpenAI characterized the critical vulnerabilities in PHP, an open-source programming language that is used to run websites and web applications, as “one of the most impactful security issues in recent memory.”
Reuters reported Wednesday that the Dutch, French, Danish and Finnish governments took websites offline. Among them was the site of the Dutch cybersecurity agency, which said it went offline as a precaution. The White House said Wednesday that it was made aware of the issue on Friday (Oct. 16), according to the report.
In addition, several European and Asian cyber agencies urged PHP users to update their sites or take the sites down immediately. The prime minister of Japan posted on X to alert website owners about the vulnerability, the report said.
The operator of Wikipedia took down some systems until it could patch them, and the Internet Archive briefly went offline to deal with the fix, per the report.
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Bloomberg reported Wednesday that the U.S. government was working with technology companies to fix the vulnerability.
Finland’s government said that as a precaution, it was taking offline all public-facing internet services, according to the report.
The United Kingdom’s National Cyber Security Centre issued an alert saying that organizations should check their systems and consider taking systems offline if the vulnerability hasn’t been fixed, per the report.
The BBC reported Wednesday that it took the pages for several of its programs offline.
When OpenAI announced the security issue Wednesday, the company said that the vulnerabilities were discovered and reported independently by Calif and Wiz; that PHP’s maintainers, supported by OpenAI, Wiz, Cloudflare and others, prepared protections before disclosing the vulnerabilities; and that organizations that use PHP were applying the fixes.
“To our knowledge, frontier AI found these vulnerabilities before attackers did, opening a Defender’s Window for maintainers and security providers to prepare fixes and protections ahead of the disclosure,” OpenAI said Wednesday.
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