Critical memory-safety and unauthenticated remote code execution (RCE) vulnerabilities were found in the core PHP engine and patched on 21 October 2026.

• CVE-2026-109618 (RCE via OOM corruption): Out-of-memory handling interrupts PHP while internal request data is only partially initialized, causing request cleanup to treat invalid data as valid.
• CVE-2026-109619 (RCE via stale global state): Request-owned internal state survives after its backing memory is freed, allowing a later request handled by the same worker to use stale state before initialization resets it.

Affected: all PHP versions from 5.4 – 8.5.11. PHP 8.1 and older are end-of-life and will not receive official fixes.

Patched versions: PHP 8.5.12 · PHP 8.4.27 · PHP 8.3.36 · PHP 8.2.35 (or newer in the same branch).

Action required: update the PHP runtime package or container image to a patched version immediately. On WordPress or shared hosting, check with the hosting provider that the update was applied. If patching isn't possible yet, isolate the internet-facing application or put it behind a Web Application Firewall (WAF) rule set.

Official patches: php.net/downloads

Status in this list follows the detected PHP version: a patched release is Resolved; anything else, including a hidden version, is NotResolved. Recheck a site to update it.