Critical Vulnerabilities in PHP Require Immediate Patching

10/21/2026 12:45 PM EDT

CISA strongly urges organizations to immediately patch the recently disclosed critical vulnerabilities in PHP, CVE-2026-109618 and CVE-2026-109619. These vulnerabilities, known as “php2shell,” allow for unauthenticated remote code execution in PHP and affect all PHP installations serving web requests. Organizations should immediately update to PHP 8.5.12, 8.4.27, 8.3.36, or 8.2.35 to fix these vulnerabilities. While CISA has not observed exploitation of these vulnerabilities as of the time of publication, they pose a risk to organizations if left unpatched. 

CISA urges organizations to take the following actions:

• Identify and inventory systems running any version of PHP across your organization. 
  • PHP is often a component of other software and prevalence may not be directly observable.
• Apply the patch immediately, prioritizing internet-facing systems.
• Organizations that cannot update immediately, or that continue to use PHP 8.1 or earlier unsupported versions, should take PHP-based systems offline until they can be patched or updated.
• A web application firewall may provide some protection until systems are updated or patched.
• Review the official PHP security advisory for guidance on patching.
• Monitor for suspicious activity, including PHP worker processes launching shells or downloading tools. 

CISA urges network defenders to review the following advisory and apply necessary updates: 

• Security Advisory: Critical Remote Code Execution Vulnerabilities, Update Now