CVE-2025-54813Network attack vector

Log integrity loss via unescaped JSON control characters

Published Aug 22, 2025 · Updated Nov 4, 2025

Improper log output neutralization in Apache Log4cxx before 1.5.0 allows remote attackers to disrupt JSON log interpretation. JSONLayout writes U+0000 through U+001F control characters into quoted output without encoding them as JSON escapes. Exploitation requires an application to log attacker-controlled bytes through JSONLayout; malformed records can mislead or break downstream parsers.

CVSS severity6.3
Medium
EPSS probability1.30%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper log output neutralization in Apache Log4cxx before 1.5.0 allows remote attackers to disrupt JSON log interpretation. JSONLayout writes U+0000 through U+001F control characters into quoted output without encoding them as JSON escapes. Exploitation requires an application to log attacker-controlled bytes through JSONLayout; malformed records can mislead or break downstream parsers.

The record

CVE
CVE-2025-54813
Published
Aug 22, 2025
Updated
Nov 4, 2025
Vendor
The Apache Software Foundation
Product
Apache Log4cxx
Classifications
CWE-117, T1565.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 22, 2025CVE publishedPublication date reported by the CVE source.
  2. Nov 4, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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

  1. Affected versionversion=0.11.0 <1.5.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Apache Software Foundation · Apache Log4cxxversion=0.11.0 <1.5.0

Published CVSS scores

6.3Apache Software FoundationCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/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.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-117Improper Output Neutralization for Logs
T1565.001Stored Data Manipulation

Public exploit references

No public exploit references are available in this record.

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

Technologies

Your stack

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Your stack

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