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

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Summary

CVECVE-2026-45077
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-07-14 18:17:17 UTC
Updated2026-07-15 15:35:50 UTC
DescriptionSymfony 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.

Risk And Classification

Primary CVSS: v4.0 8.3 HIGH from [email protected]

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS: 0.005510000 probability, percentile 0.423560000 (date 2026-07-15)

Problem Types: CWE-502 | CWE-668 | CWE-502 CWE-502: Deserialization of Untrusted Data | CWE-668 CWE-668: Exposure of Resource to Wrong Sphere

VersionSourceTypeScoreSeverityVector
4.0[email protected]Secondary8.3HIGHCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N/E:X/C...
4.0CNADECLARED8.3HIGHCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N
3.1[email protected]Primary8.6HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H

CVSS v4.0 Breakdown

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
Present
Privileges Required
None
User Interaction
None
Confidentiality
Low
Integrity
Low
Availability
High
Sub Conf.
None
Sub Integrity
None
Sub Availability
None

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Sensiolabs Symfony All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Symfony Symfony affected < 5.4.52 Not specified
CNA Symfony Symfony affected >= 6.0.0-BETA1, < 6.4.40 Not specified
CNA Symfony Symfony affected >= 7.0.0-BETA1, < 7.4.12 Not specified
CNA Symfony Symfony affected >= 8.0.0-BETA1, < 8.0.12 Not specified
CNA Symfony Monolog-bridge affected < 5.4.52 Not specified
CNA Symfony Monolog-bridge affected >= 6.0.0-BETA1, < 6.4.40 Not specified
CNA Symfony Monolog-bridge affected >= 7.0.0-BETA1, < 7.4.12 Not specified
CNA Symfony Monolog-bridge affected >= 8.0.0-BETA1, < 8.0.12 Not specified

References

ReferenceSourceLinkTags
github.com/symfony/symfony/commit/0891b2f293896c488e26943dc034334364b77fc4 [email protected] github.com Patch
github.com/symfony/symfony/releases/tag/v5.4.52 [email protected] github.com Product, Release Notes
github.com/symfony/symfony/releases/tag/v6.4.40 [email protected] github.com Product, Release Notes
github.com/symfony/symfony/releases/tag/v8.0.12 [email protected] github.com Product, Release Notes
github.com/symfony/symfony/security/advisories/GHSA-m7v2-7gxm-vc2v [email protected] github.com Patch, Vendor Advisory
github.com/symfony/symfony/releases/tag/v7.4.12 [email protected] github.com Product, Release Notes
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis
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