CVE-2025-54812Network attack vector

Stored XSS via unescaped HTMLLayout logger names

Published Aug 22, 2025 · Updated Nov 4, 2025

Stored XSS in HTMLLayout in Apache Log4cxx before 1.5.0 allows remote attackers to execute script via crafted logger names. HTMLLayout appends event->getLoggerName() to a quoted title attribute without escaping HTML metacharacters, allowing the name to break the document structure. Exploitation requires HTMLLayout, an attacker-controlled logger name that emits a message, and a user opening the resulting log file in a browser.

CVSS severity2.1
Low
EPSS probability1.19%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Stored XSS in HTMLLayout in Apache Log4cxx before 1.5.0 allows remote attackers to execute script via crafted logger names. HTMLLayout appends event->getLoggerName() to a quoted title attribute without escaping HTML metacharacters, allowing the name to break the document structure. Exploitation requires HTMLLayout, an attacker-controlled logger name that emits a message, and a user opening the resulting log file in a browser.

The record

CVE
CVE-2025-54812
Published
Aug 22, 2025
Updated
Nov 4, 2025
Vendor
The Apache Software Foundation
Product
Apache Log4cxx
Classifications
CWE-117, T1203
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

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=0 <1.5.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Apache Software Foundation · Apache Log4cxxversion=0 <1.5.0

Published CVSS scores

2.1Apache Software FoundationCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:L/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.

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

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
T1203Exploitation for Client Execution

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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo