CVE-2025-54812
Apache Log4cxx: Improper HTML escaping in HTMLLayout
- State
- Published
- Severity
- 2.1 Low
- Published
- Aug 22, 2025
- Updated
- Nov 4, 2025
- Reserved
- Jul 30, 2025
Description
Improper Output Neutralization for Logs vulnerability in Apache Log4cxx.
When using HTMLLayout, logger names are not properly escaped when writing out to the HTML file. If untrusted data is used to retrieve the name of a logger, an attacker could theoretically inject HTML or Javascript in order to hide information from logs or steal data from the user. In order to activate this, the following sequence must occur:
* Log4cxx is configured to use HTMLLayout.
* Logger name comes from an untrusted string
* Logger with compromised name logs a message
* User opens the generated HTML log file in their browser, leading to potential XSS
Because logger names are generally constant strings, we assess the impact to users as LOW
This issue affects Apache Log4cxx: before 1.5.0.
Users are recommended to upgrade to version 1.5.0, which fixes the issue.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 2.1 Low | CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N | apache |
Weaknesses
- CWE-117 Improper Output Neutralization for Logs
Affected Products
| Product | Versions |
|---|---|
Apache Log4cxxApache Software Foundation |
|
References
- https://logging.apache.org/security.html#CVE-2025-54812vendor-advisory
- https://github.com/apache/logging-log4cxx/pull/509patch
- https://github.com/apache/logging-log4cxx/pull/514patch
- https://lists.debian.org/debian-lts-announce/2025/10/msg00002.html
- http://www.openwall.com/lists/oss-security/2025/08/22/2
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