Cloudanix VulnDB

CVE-2026-45077

Critical · 9.8

Symfony has Unauthenticated PHP Object Deserialization in MonologBridge server:log Listener

CVSS

9.8

EPSS

0.7%

Published

May 27, 2026

CISA due date

—

The record

`Symfony\Bridge\Monolog\Command\ServerLogCommand` (the `server:log` console command) is a development-time helper that opens a TCP listener and displays log records pushed to it by the application's logging pipeline. Two unsafe defaults combine into a remotely reachable PHP object-deserialization sink: 1. The listener binds to `0.0.0.0:9911` by default; it accepts connections on every interface, not only loopback. 2. Each received frame is processed as `unserialize(base64_decode($message))` without an `allowed_classes` allowlist, without authentication, and without any integrity check. The decoded value is then passed to `displayLog(..., array $record)` which assumes (without validating) that the result is an array. Any host that can reach TCP port 9911 on a machine running `server:log` can therefore submit attacker-chosen serialized PHP payloads. The minimum impact is an unauthenticated denial of service (sending a non-array, e.g. `serialize(new stdClass())`, crashes the listener with a type error). Object injection with magic-method side effects (`__wakeup()` / `__destruct()` / etc.) is reachable before the array type-check fires; full remote code execution is environment-dependent and contingent on usable gadget chains in the autoload set of the target process.

Affected packages

Ecosystem Package Introduced Fixed

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