CVE-2026-45077Public exploitNetwork attack vector

Unauthenticated listener crash via unsafe PHP deserialization

Published Jul 14, 2026 · Updated Jul 14, 2026

Unsafe deserialization in Symfony Monolog Bridge before branch fixes 5.4.52, 6.4.40, 7.4.12, and 8.0.12 allows remote attackers to crash server:log. The listener binds to 0.0.0.0:9911 and passes base64-decoded frames to unserialize() without authentication, integrity checks, or an allowed_classes restriction. The development-time command must be running with TCP port 9911 reachable; a non-array payload crashes it, while gadget effects depend on autoloaded classes.

CVSS severity8.3
High
EPSS probability0.67%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Unsafe deserialization in Symfony Monolog Bridge before branch fixes 5.4.52, 6.4.40, 7.4.12, and 8.0.12 allows remote attackers to crash server:log. The listener binds to 0.0.0.0:9911 and passes base64-decoded frames to unserialize() without authentication, integrity checks, or an allowed_classes restriction. The development-time command must be running with TCP port 9911 reachable; a non-array payload crashes it, while gadget effects depend on autoloaded classes.

The record

CVE
CVE-2026-45077
Published
Jul 14, 2026
Updated
Jul 14, 2026
Vendor
Symfony
Product
Symfony Monolog Bridge
Classifications
CWE-668, CWE-502, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 14, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 14, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 5.4.52
  2. Affected versionversion=>= 6.0.0-BETA1, < 6.4.40
  3. Affected versionversion=>= 7.0.0-BETA1, < 7.4.12
  4. Affected versionversion=>= 8.0.0-BETA1, < 8.0.12

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Symfony · Symfony Monolog Bridgeversion=< 5.4.52; version=>= 6.0.0-BETA1, < 6.4.40; version=>= 7.0.0-BETA1, < 7.4.12; version=>= 8.0.0-BETA1, < 8.0.12
Symfony · Symfonyversion=< 5.4.52; version=>= 6.0.0-BETA1, < 6.4.40; version=>= 7.0.0-BETA1, < 7.4.12; version=>= 8.0.0-BETA1, < 8.0.12

Published CVSS scores

8.1GitHub Advisory DatabaseCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U
8.6NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H
8.3GitHub, Inc.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

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-668Exposure of Resource to Wrong Sphere
CWE-502Deserialization of Untrusted Data
T1499.004Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

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