Anyone running a website on PHP, the language behind a large share of the web, needs to install the fix released October 21. Regular users have nothing to install, since patching falls to the companies running the sites.
The flaws, nicknamed "PHP2SHELL", could let attackers take over servers running PHP. OpenAI said it spent two months leading a coalition of PHP maintainers, security researchers and security companies on the response. According to OpenAI, the security firm Calif found one critical flaw using GPT-5.6 Sol, under an OpenAI program called Patch the Planet. Wiz found and reported both vulnerabilities independently, the company said.
OpenAI President Greg Brockman said the bug had existed for 14 years. A smaller version surfaced in 2024 but was not treated as serious. Calif found a version in August, and OpenAI's own team independently found a more complete one in September. Planned disclosure was October 22, but details leaked, so PHP's maintainers shipped the fixes a day early.
The visible damage was real. Wikipedia went down, and the Wikimedia Foundation tied the outage to the PHP flaws. Downdetector showed trouble at sites including Duolingo, Capital One and the Internet Archive, though most have not said whether PHP was the cause. Japan's prime minister publicly urged site owners to patch that night.
The credit is shared, and OpenAI's account of its own role deserves that context: Wiz found both bugs without OpenAI's model, and PHP's maintainers did the fixing. The sturdier point is Brockman's. Disclosure today is "slow and manual", and a 2024 near-miss that was waved off shows how triage can fail even at human pace.
OpenAI admits the same tools could help attackers write exploits faster. It has pledged $1 billion in subsidized access to its security tools for groups protecting essential services, and it released a PHP version checker. It also floated letting governments or other authorized defenders scan the internet for vulnerable systems and, in extreme cases, patch them directly. Who would hold that authority, and over whose servers, is the question the proposal leaves open.