PHP at a glance
PHP 8.5.12, 8.4.27, 8.3.36 and 8.2.35 fix CVE-2026-109618 and CVE-2026-109619, both rated critical (CVSS v4 9.2). Researchers using AI tools showed unauthenticated code execution against WordPress, Drupal and Joomla.
PHP: status
- Affected
- PHP 8.5 before 8.5.12
- PHP 8.4 before 8.4.27
- PHP 8.3 before 8.3.36
- PHP 8.2 before 8.2.35
- End-of-life PHP 8.1 and older (no official release; minimal source backports for 7.4, 8.0 and 8.1)
- Web SAPIs including Apache mod_php and PHP-FPM; FrankenPHP and LSAPI likely affected
- Status as of
- Discovered by
- Calif (LLM-assisted review under OpenAI's Patch the Planet), Wiz Research (Wiz Atlas with Gemini 4 Argon and GPT-5.6 Sol), and OpenAI · Found by an AI system
What changed with PHP
On October 21, 2026, the PHP project shipped security releases for every supported branch and urged all users to update. The two bugs sit in PHP's own request handling, not in any framework. CVE-2026-109618 lets a request that hits the memory limit at the wrong moment leave half-built data behind, which PHP later trusts; on Apache with mod_php this can be triggered before any application code runs, and the project confirmed code execution with default settings. CVE-2026-109619 leaves internal state pointing at memory from an earlier request, so the next request on the same worker can use freed memory.
Almost every PHP site that serves web traffic is in scope. The advisories list mod_php and PHP-FPM paths and say FrankenPHP and LSAPI are likely affected; Calif traces the oldest affected code back to PHP 5.4. Wiz demonstrated pre-authentication takeover of stock WordPress, Drupal and Joomla images. PHP 8.1 and older get no official release, only minimal source backports linked from the advisory, while Linux distributions and long-term-support vendors received patches in advance.
The flaws were reported by Calif, using LLM-assisted source review under OpenAI's Patch the Planet program, by Wiz Research, which credits its Wiz Atlas platform with Gemini 4 Argon and GPT-5.6 Sol, and by OpenAI. The PHP Foundation says people still make every call and write every patch, and that the embargo leaked early: a proof-of-concept video was posted by mistake and fixed container images appeared hours ahead of the coordinated release. Cognition published open-source agent skills that walk a coding agent through a read-only inventory and an approval step before patching.
How to fix it: PHP
1. Update
Upgrade to PHP 8.5.12, 8.4.27, 8.3.36 or 8.2.35 (or your Linux distribution's patched package), then restart every PHP worker. The PHP project says updating is the only complete fix.
php.net (opens in a new tab)2. Workaround
If you cannot patch at once (CVE-2026-109618): set memory_limit=-1 via php_admin_value in the FPM pool or Apache config, cap post_max_size (8M without uploads, 32M with uploads), enforce request limits at the web server or proxy, and use container or cgroup memory limits. These reduce exposure but do not make PHP safe.
php.net (opens in a new tab)3. Workaround
Interim step for CVE-2026-109619: set session.upload_progress.enabled=0 in php.ini, the FPM pool or server config (not with ini_set() or .user.ini) and restart all workers; on PHP 8.5 also set fatal_error_backtraces=0.
github.com (opens in a new tab)4. Monitor
Watch for unusual multipart requests followed by memory-limit errors, bursts of HTTP 500 responses, oversized or malformed PHPSESSID cookies, and unexplained PHP worker restarts.
wiz.io (opens in a new tab)5. Agent instruction
If an AI coding agent will do the upgrade, give it the instruction below. It follows the rules of Cognition's open-source fix-php-vuln skill: read-only inventory first, explicit approval, confirmed versions, and tests before and after.
github.com (opens in a new tab)
Instruction for your AI agent
Before changing anything, make a read-only inventory of every PHP runtime this project uses (Dockerfiles, base images, OS packages, infrastructure-as-code) and show it to me as one table. Do not edit, install or restart anything until I approve the specific repositories. Patch only to a fixed release you have confirmed exists (PHP 8.5.12, 8.4.27, 8.3.36, 8.2.35 or a later patched release in the same branch, or the distribution's patched package); never guess a version. Run the tests in the built production image before and after, treat new failures or deprecation warnings as regressions, and open one pull request per repository with a rollback target.
Based on the official guidance linked below. Review it before giving it to an agent that can change your systems.
Advisories
Where to compare PHP
Independent leaderboards and official resources for comparing this model yourself. Rankings change often; each site shows its own current data.
Why PHP matters for businesses
PHP still powers a large share of small-business and agency websites, including most WordPress installs. This case shows AI tools finding decade-old bugs in core infrastructure, and attackers getting proof-of-concept code within hours. If you or your clients run PHP, confirm with each host that the runtime is patched rather than assuming the CMS update covers it, and keep humans approving any agent-driven upgrade.
PHP updates since publication
Dated changes since publication. The original article text above is kept as written on its date.
Status (Updated)Fixed
CISA added CVE-2026-109618 and CVE-2026-109619 to its Known Exploited Vulnerabilities catalog on October 26, 2026.
cisa.gov (opens in a new tab)
Sources for this story
- Security advisory: Critical remote code execution vulnerabilities, update now (opens in a new tab)Official
PHP · php.net
- RCE via OOM corruption (GHSA-w8hw-w9fx-j79w) (opens in a new tab)Official
php/php-src on GitHub · github.com
- RCE via stale global state (GHSA-6wmf-4rv5-p3rp) (opens in a new tab)Official
php/php-src on GitHub · github.com
- Today's PHP security release and how we're strengthening PHP security (opens in a new tab)Official
The PHP Foundation · thephp.foundation
- PHP2Shell: AI uncovers critical RCE vulnerabilities (opens in a new tab)Official
Wiz Research · wiz.io
- PHP2Shell (opens in a new tab)Official
Calif · calif.io
- Devin Vulnerability Fixes (agent skills) (opens in a new tab)Official
Cognition on GitHub · github.com
Last verified: . IA Compa summarizes public announcements for business readers. We are not affiliated with the companies mentioned. Always confirm details, pricing, and availability with the official source.
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- #patch-now