CVE-2026-45077

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

HIGH

8.6

CVSS Score

Published: July 14, 2026 at 05:46 PM UTC

Updated: July 15, 2026 at 03:54 PM UTC

3 products affected across 2 vendorsSymfonySymfonyMonolog Bridge

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Severity

HIGH8.6

Exploit prediction

EPSS 0.7%

SSVC

No known exploit

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Symfony · Sensiolabsdrupal

95%

v < 5.4.526.0.0 ≤ v < 6.4.407.0.0 ≤ v < 7.4.128.0.0 ≤ v < 8.0.12

Affected range stops below 5.4.52, so it looks safe — our inference, not a vendor statement

Affected range stops below 6.4.40, so it looks safe — our inference, not a vendor statement

Affected range stops below 7.4.12, so it looks safe — our inference, not a vendor statement

Affected range stops below 8.0.12, so it looks safe — our inference, not a vendor statement

Monolog Bridge · Symfony

60%

v < 5.4.52v < 6.4.40v < 7.4.12v < 8.0.12

Affected range stops below 5.4.52, so it looks safe — our inference, not a vendor statement

Affected range stops below 6.4.40, so it looks safe — our inference, not a vendor statement

Affected range stops below 7.4.12, so it looks safe — our inference, not a vendor statement

Affected range stops below 8.0.12, so it looks safe — our inference, not a vendor statement

Symfony · Symfonycomposer

60%

v < 5.4.52v < 6.4.40v < 7.4.12v < 8.0.12

Affected range stops below 5.4.52, so it looks safe — our inference, not a vendor statement

Affected range stops below 6.4.40, so it looks safe — our inference, not a vendor statement

Affected range stops below 7.4.12, so it looks safe — our inference, not a vendor statement

Affected range stops below 8.0.12, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

References (6)

x_refsource_CONFIRMPatchVendor Advisory

Source: cverecord

https://github.com/symfony/symfony/security/advisories/GHSA-m7v2-7gxm-vc2v

x_refsource_MISCPatch

Source: cverecord

https://github.com/symfony/symfony/commit/0891b2f293896c488e26943dc034334364b77fc4

x_refsource_MISCProductRelease Notes

Source: cverecord

https://github.com/symfony/symfony/releases/tag/v5.4.52

x_refsource_MISCProductRelease Notes

Source: cverecord

https://github.com/symfony/symfony/releases/tag/v6.4.40

x_refsource_MISCProductRelease Notes

Source: cverecord

https://github.com/symfony/symfony/releases/tag/v7.4.12

x_refsource_MISCProductRelease Notes

Source: cverecord

https://github.com/symfony/symfony/releases/tag/v8.0.12

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

8.6HIGH[email protected]

Attack Vector: NETWORK
Complexity: LOW
Privileges: NONE
User Interaction: NONE
Scope: UNCHANGED
Confidentiality: LOW
Integrity: LOW
Availability: HIGH

Vector?

Quick Info

StatusANALYZED

CWE

CWE-502CWE-668

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