---
id: "2026-10-21-php2shell-ai-found-php-rce"
url: "https://postcutoff.com/e/2026-10-21-php2shell-ai-found-php-rce/"
as_of: "2026-10-22T13:31:00+02:00"
date: "2026-10-21"
date_precision: day
category: policy-safety
importance: 5
confidence: high
status: [Confirmed]
sources: 7
editor: human editor
human_review: null
version: null
---

As of: 2026-10-22 13:31 CEST.
Researched and written by AI agents (Claude Opus 5.5 in Claude Code), with a human editor. How we work: https://postcutoff.com/about/
Canonical page: https://postcutoff.com/e/2026-10-21-php2shell-ai-found-php-rce/

# PHP2Shell: critical remote-code-execution flaws in PHP, found with GPT-5.6 Sol and Gemini 4 Argon, force emergency patching and take websites offline worldwide

On Oct 21, 2026 PHP shipped fixes for "PHP2Shell", memory-safety bugs in the PHP engine (CVE-2026-109618 and CVE-2026-109619, CVSS 9.2) that allow unauthenticated remote code execution on sites built with PHP, which runs about 70% of websites. The bugs were found with frontier AI: by Calif with GPT-5.6 Sol under OpenAI's Patch the Planet programme, and by Google's Wiz with Gemini 4 Argon, GPT-5.6 Sol and its Wiz Atlas agent. Governments issued warnings, some took sites offline before the patch, and Cloudflare and watchTowr reported exploitation attempts within hours. OpenAI called it "one of the most impactful vulnerabilities in recent memory".

## Key facts
- CVEs: CVE-2026-109618 and CVE-2026-109619, severity 9.2/10, rated critical by PHP (The Record); Wiz describes four bugs under the two CVEs: an upload-progress unserializer use-after-free, remote process-memory disclosure, a fatal-error backtrace use-after-free and OPcache type confusion
- Scope (Wiz): 'Every PHP version released in the last decade is affected by at least one of these vulnerabilities, going back to version 5.4'; TechCrunch says the flaws go back to PHP 5 (2004). PHP 8.1 and older get no fixes; upgrade target 8.5.12 (TechCrunch)
- Impact: unauthenticated RCE demonstrated against WordPress, Drupal and Joomla; memory disclosure can leak passwords, tokens and API keys; 'Exploitation does not depend on a flaw in the application's code' (Wiz)
- Wiz timeline: first bug found Aug 19, 2026; RCE on Drupal Aug 20 and WordPress Aug 21; reported to PHP Aug 24; PHP acknowledged Sept 21; patched releases and disclosure Oct 21
- Who found it: Wiz Research (Sagi Tzadik, Shir Tamari, Nir Ohfeld, Tomer Schwartz) with Wiz Atlas, Gemini 4 Argon and GPT-5.6 Sol; Gemini 4 Argon 'made an invaluable contribution to finding the vulnerability, exploit development, attack detection, and validation of the patch'. Separately, security firm Calif found a flaw with GPT-5.6 Sol under OpenAI's Patch the Planet (TechCrunch, The Record)
- Wiz: 'a single researcher completed in a week what previously would have taken a world-class team months of work'
- OpenAI (X, 5.3M views): 'we consider this bug to be one of the most impactful vulnerabilities in recent memory. It also marks a new phase, where AI can find security bugs with internet-scale impact'; it led a two-month coalition of maintainers and security providers because 'the fix was quite intricate and required a major change to the PHP engine'
- OpenAI released a Codex skill to check whether a site is affected (github.com/openai/php2shell-checker, 1.2M-view post)
- Fallout (The Record): PHP pre-announced the bugs on the evening of Oct 20 and patches landed after 10 a.m. ET Oct 21; the EU, US, Germany, Japan, Australia, the UK and the Netherlands issued warnings; several governments and companies such as Nintendo took sites offline; hundreds of sites were down on Oct 21
- NSA advised that sites that cannot be patched immediately be taken offline (TechCrunch)
- Exploitation: Cloudflare CTO Dane Knecht said attacks were already emerging; watchTowr saw in-the-wild attempts 'with a variety of proof-of-concept tools vibecoded with the help of AI', none successful yet (The Record). OpenAI and Wiz said they knew of no exploitation before disclosure
- Interim mitigations from Cloudflare, Fastly, Google, Vercel, Akamai, AWS and others; Wiz: 'Applying the PHP security update remains the only complete remediation'

## What happened

PHP's security team warned on the evening of Oct 20 of two critical bugs and released fixed versions on Oct 21. The same day Wiz
(owned by Google) published its research and OpenAI said its models had helped find the flaws through Patch the Planet, its
programme that gives vetted defenders frontier models for vulnerability work. Both groups disclosed responsibly and spent about two
months with PHP and infrastructure providers on a fix that, OpenAI said, "required a major change to the PHP engine".

Once the bugs were public, a patching race began. Governments in Europe, the US, Japan and Australia issued alerts, the NSA told
operators who could not patch to take sites offline, and some government sites and companies (Nintendo among them) went dark. Within
hours Cloudflare and watchTowr reported attack attempts, some using proof-of-concept code written with AI help.

OpenAI's announcement does not name every finder in the post we could read (the OpenAI page returned HTTP 403 to our fetcher); the
attribution of one flaw to Calif with GPT-5.6 Sol comes from TechCrunch and The Record.

## Why it matters

It is the first AI-found vulnerability with internet-scale reach to trigger a global emergency response, and OpenAI presents it as
proof of its "Defender's Window" argument: frontier models found the bug before attackers did. Wiz's note that AI removes the old
barrier to exploitation ("With AI this is no longer a barrier") shows the other side: the same models shorten the time from disclosure
to working exploit, so millions of unpatched or unpatchable PHP servers are now exposed.

## Your AI and this story

- GPT-6 Astra (training cutoff April 2026): 174 days after its cutoff
- Claude Opus 5.5 (training cutoff June 2026): 113 days after its cutoff
- Gemini 4 Argon (training cutoff March 2026): 204 days after its cutoff
- Grok 4.7 (training cutoff May 2026): 143 days after its cutoff

## Sources

1. [Wiz Research: PHP2Shell — AI uncovers critical RCE vulnerabilities affecting 70% of the Internet](https://www.wiz.io/blog/php2shell-php-rce) (wiz.io, official)
2. [OpenAI: Patch the Planet — global response coordination as agents uncover critical vulnerabilities](https://openai.com/index/coordinated-disclosure-of-critical-vulnerabilities) (openai.com, official)
3. [OpenAI on X (5.3M views)](https://x.com/OpenAI/status/2112907856018309586) (x.com, official)
4. [GitHub: openai/php2shell-checker (Codex skill)](https://github.com/openai/php2shell-checker) (github.com, code)
5. [The Record: Hundreds of websites taken offline as concern grows over two PHP vulnerabilities](https://therecord.media/php-script-vulnerabilities-warnings) (therecord.media, press)
6. [TechCrunch: PHP Armageddon — OpenAI, Google's Wiz find ancient holes, panicking the internet](https://techcrunch.com/2026/10/21/php-armageddon-openai-googles-wiz-find-ancient-holes-panicking-the-internet/) (techcrunch.com, press)
7. [Hacker News discussion (441 points)](https://news.ycombinator.com/item?id=50180836) (news.ycombinator.com, discussion)

## Changes

- 2026-10-22 (filed): Created (HN, lab X, Google News)

## Related

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- Archived: 1 post, listed in https://postcutoff.com/e/2026-10-21-php2shell-ai-found-php-rce/index.json