PHP Warns of Another Unpatched RCE Risk Two Days After Emergency PHP2Shell Patches
AI-summarised brief · reviewed before publication
PHP issued an informational advisory on October 23 warning of a new remote code execution (RCE) vector, CVE‑2026‑115560, that affects web applications with a rare configuration. The flaw requires the session.serialize_handler setting to be switched from php_binary or php_serialize to php at runtime, before session_start(), while session upload progress remains enabled. Because this setup is uncommon, the PHP project will not release an emergency patch; instead it advises administrators to disable session.upload_progress.enabled until the next routine release. The advisory follows the October 21 emergency updates that patched two critical PHP2Shell flaws (CVE‑2026‑109618 and CVE‑2026‑109619) in PHP 8.5.12, 8.4.27, 8.3.36 and 8.2.35. No exploitation of the new issue has been reported, and the earlier PHP2Shell exploits have seen a surge in attempts but have not yielded successful code execution.
💡 Why It Matters
- · Disabling session upload progress provides an immediate, low‑cost mitigation for a vulnerability that could otherwise let attackers execute code on servers with a specific, but plausible, configuration.