Symfony is a PHP framework for web and console applications and a set of reusable PHP components. Prior to 5.4.52, 6.4.40, 7.4.12, and 8.0.12, the server:log listener (Symfony\Bridge\Monolog\Command\ServerLogCommand) binds to 0.0.0.0:9911 by default and processes each received frame with unserialize(base64_decode($message)) without authentication, integrity checks, or an allowed_classes allowlist, allowing any reachable host to submit attacker-chosen serialized PHP payloads that can crash the listener and may trigger object-injection gadget effects. This issue is fixed in versions 5.4.52, 6.4.40, 7.4.12, and 8.0.12.
https://github.com/symfony/symfony/security/advisories/GHSA-m7v2-7gxm-vc2v
https://github.com/symfony/symfony/releases/tag/v8.0.12
https://github.com/symfony/symfony/releases/tag/v7.4.12
https://github.com/symfony/symfony/releases/tag/v6.4.40
https://github.com/symfony/symfony/releases/tag/v5.4.52
https://github.com/symfony/symfony/commit/0891b2f293896c488e26943dc034334364b77fc4
Published: 2026-07-14
Updated: 2026-07-14
Base Score: 7.5
Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P
Severity: High
Base Score: 9.8
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Severity: Critical
Base Score: 8.3
Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N
Severity: High
EPSS: 0.00987