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Vulnerability · Published Oct 13, 2026 · Assigned by GitHub_M

CVE-2026-82416FrankenPHP: Cross-request PHP session ID leak in worker mode when the session extension is a shared module

High 7.7

In plain English

A high-severity race condition in frankenphp from php. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 22% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.7High
Exploit odds (30 days)0.3%top 78.0% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Gogithub.com/dunglas/frankenphp1.12.5GHSA-v3ph-cgqh-r8p5
Gogithub.com/dunglas/frankenphp1.12.5GO-2026-6797

Affected products (as reported)

VendorProductVersions
php frankenphp < 1.12.5

Weakness: CWE-362, CWE-488 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L

References