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PHP2Shell

A named vulnerability event covering 2 CVEs.

Technical briefing

PHP2Shell: two critical PHP runtime RCE flaws exploited in the wild; patch PHP now

CVE-2026-109618 (out-of-memory corruption after longjmp) and CVE-2026-109619 (stale global state) are flaws in the PHP runtime itself, not in one application. They are reached through HTTP requests to PHP web workers. The highest confirmed risk is Apache mod_php, where an unauthenticated request can lead to remote code execution as the web worker user. Both are rated CVSS 9.2 (v4.0), and the vulnerability records list both in CISA KEV.

Mitigations

  1. Update every PHP runtime to a fixed version and restart all PHP workers Upgrade to 8.5.12, 8.4.27, 8.3.36 or 8.2.35. On distro or vendor builds, verify the vendor explicitly addresses both CVEs, since fixes may be backported without a version change. Update every runtime, including containers, appliances, control panels and PHP-FPM pools. Updating a PHP application (WordPress etc.) alone is not sufficient.
  2. Inventory and prioritise exposed PHP Find the PHP version and SAPI the web server actually uses, which may differ from the CLI version. Prioritise internet-facing services, especially Apache mod_php, and shared hosting with persistent workers.
  3. Disable session upload progress on unpatched hosts (session.upload_progress.enabled=0) MyCERT says this fully mitigates the execution path of the public script and urges it on any unpatched host. It also notes PHP's recommendation of the same setting for the separate CVE-2026-115560.
  4. Restrict PAN-OS management interface access Palo Alto Networks advises allowing management access only from a jump box. Risk is highest when the management interface is reachable from the internet. Threat Prevention customers can enable Threat IDs 543004, 97622, 97623, 97624 and 97625 (content version 9162 or later), which requires routing MGT traffic through a data-plane port and enabling threat prevention on inbound management traffic. Frontier Virtual Patching customers on PAN-OS 12.2.4 or later received Threat ID 543004.
  5. Restrict NetScaler management interfaces with ACLs Citrix points to its ACL-based guidance while it updates the PHP used by NetScaler management interfaces.
  6. Apply Cisco fixes or bug-listed workarounds where affected Cisco lists fixed releases for Expressway (15.5.21), Duo Access Gateway (3.2.0) and URWB (26.2.1.9, Nov 2026). Workarounds for URWB and Expressway are in the bug IDs. Check the Cisco Bug Search Tool for platform details.
  7. Check other vendor advisories Fortinet lists products under investigation (FortiDDoS, FortiDDoS-F, FortiClient Cloud Services, FortiSOAR, FortiSOAR PaaS) and OT IPS signatures released in version 37.316. Zyxel says no currently available products are affected. Siemens lists many products as not affected because PHP is not present.