AI security company Calif used GPT-5.6 Sol to discover a critical PHP vulnerability affecting about 70% of websites

Researchers using GPT-5.6 Sol found massively critical flaw in PHP, which runs about 70% of websites, knocked major sites offline as operators rushed to patch.

Calif, an AI security firm, who found this, said in a statement that the vulnerabilities could put 70% of the world’s websites at risk if they aren’t patched quickly, and called them “the most severe vulnerabilities ever discovered by AI, if not in all of software history.”

> PHP rushed out fixes as it could let attackers without accounts take over web servers.

> Both bugs score 9.2 on the CVSS severity scale and affect PHP versions as old as 5.4.

> When a request hits PHP’s memory cap at the wrong moment, PHP frees memory but keeps pointers to it, which a later request on that worker can hijack.

> Auditors spotted the weakness in 2024, but the fix stalled for months, partly because nobody had shown a practical attack.

> Wiz, a cloud security company, now owned by Google, says the models let one researcher finish in a week what once took a top team months.

> A leak of the CVE numbers forced PHP to ship a day early, and Cloudflare now reports early attack attempts.