AI finds 14-year-old PHP flaws: PHP2Shell

Two flaws in the PHP project's PHP let attackers take over web servers without logging in. PHP fixed both on the 21st of October 2026, its advisory says.

AI helped find them. Calif found one flaw with OpenAI's GPT-5.6 Sol, and Wiz found both, OpenAI wrote that day, as quoted by PPC Land.

Two flaws, CVE-2026-109618 and CVE-2026-109619, both rated 9.2 out of 10

Both allow remote code execution, a way to run an attacker's commands on a server, PHP's advisory says.

The first starts when PHP runs out of memory while it sets up a request. The second lets one request use data left behind by an earlier one, PHP wrote on GitHub.

Below we break down who found the flaws, and how the AI helped

Calif began auditing on the 30th of July 2026 and reported on the 11th of August, the PHP Foundation wrote. OpenAI reported the same root cause that day.

Calif's AI agent traced the bug to nested form data, Calif's write-up says. An AI model then turned the pattern into a checklist for more searches.

Calif wrote that it used only models open to everyone for the first find. Wiz found its first bug on the 19th of August with Google's Gemini 4 Argon and GPT-5.6 Sol, its blog says.

"A single researcher completed in a week what previously would have taken a world-class team months of work," Wiz wrote.

The oldest affected code is PHP 5.4.0, from 2012

Calif and Wiz both wrote that the oldest affected code is PHP 5.4.0. PHP's changelog dates it to the 1st of March 2012, 14 years ago by our arithmetic.

Who is affected and what to do now

Every PHP install that serves web pages is at risk, PHP said, as quoted by Huntress. The fixed versions are 8.5.12, 8.4.27, 8.3.36 and 8.2.35.

PHP 8.1 and older get no official release, Tenable wrote. Updating is the only complete fix, PHP's advisory says.

What is confirmed and what is not

TechCrunch wrote that the flaws sit in every version since PHP 5 of 2004. Calif and Wiz name PHP 5.4.0 as the oldest.

Key facts

Two PHP flaws allow remote takeover, fixed on the 21st of October 2026.

Found by Calif with OpenAI's GPT-5.6 Sol, and by Wiz with Gemini 4 Argon.

Oldest affected code: PHP 5.4.0 of 2012.

Fixed versions: 8.5.12, 8.4.27, 8.3.36 and 8.2.35.