php FrankenPHP up to 1.12.4 Worker Mode frankenphp_reset_session_state session fixiation

Summaryinfo

A vulnerability described as critical has been identified in php FrankenPHP up to 1.12.4. This impacts the function frankenphp_reset_session_state of the component Worker Mode. Such manipulation leads to session fixiation. This vulnerability is referenced as CVE-2026-82416. It is possible to launch the attack remotely. No exploit is available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability, which was classified as critical, has been found in php FrankenPHP up to 1.12.4. Affected by this issue is the function frankenphp_reset_session_state of the component Worker Mode. The manipulation with an unknown input leads to a session fixiation vulnerability. Using CWE to declare the problem leads to CWE-384. Authenticating a user, or otherwise establishing a new user session, without invalidating any existing session identifier gives an attacker the opportunity to steal authenticated sessions. Impacted is confidentiality, integrity, and availability. CVE summarizes:

FrankenPHP is a modern application server for PHP. Prior to 1.12.5, FrankenPHP worker mode can retain PHP session state between requests when the session extension is loaded as a shared module and is unavailable through HAVE_PHP_SESSION at compile time. In this build configuration, frankenphp_reset_session_state() is compiled out, PS(id) can survive a request boundary, and a subsequent session_start() can ignore the new request's cookie because an identifier is already present. Under concurrent requests, session_id() can therefore return another client's identifier or a stale identifier from a previous request on the same worker thread, causing cross-user session exposure, possible session hijacking, and intermittent logout behavior. Builds with the session extension statically linked, including the official static binaries and Docker images, are not affected. This issue is fixed in version 1.12.5.

The advisory is shared for download at github.com. This vulnerability is handled as CVE-2026-82416 since 08/29/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. There are known technical details, but no exploit is available.

Upgrading to version 1.12.5 eliminates this vulnerability.

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Productinfo

Type

• Programming Language Software

Vendor

• php

Name

• FrankenPHP

Version

• 1.12.0
• 1.12.1
• 1.12.2
• 1.12.3
• 1.12.4

License

• open-source

Website

• Product: https://github.com/php/frankenphp/

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