Headline
GHSA-qqpg-mvqg-649v: Logback allows an attacker to instantiate classes already present on the class path
ACE vulnerability in configuration file processing by QOS.CH logback-core up to and including version 1.5.24 in Java applications, allows an attacker to instantiate classes already present on the class path by compromising an existing logback configuration file.
The instantiation of a potentially malicious Java class requires that said class is present on the user’s class-path. In addition, the attacker must have write access to a configuration file. However, after successful instantiation, the instance is very likely to be discarded with no further ado.
- GitHub Advisory Database
- GitHub Reviewed
- CVE-2026-1225
Logback allows an attacker to instantiate classes already present on the class path
Low severity GitHub Reviewed Published Jan 22, 2026 to the GitHub Advisory Database • Updated Jan 22, 2026
Package
maven ch.qos.logback:logback-core (Maven)
Affected versions
< 1.5.25
ACE vulnerability in configuration file processing by QOS.CH logback-core up to and including version 1.5.24 in Java applications, allows an attacker to instantiate classes already present on the class path by compromising an existing logback configuration file.
The instantiation of a potentially malicious Java class requires that said class is present on the user’s class-path. In addition, the attacker must have write access to a configuration file. However, after successful instantiation, the instance is very likely to be discarded with no further ado.
References
- https://nvd.nist.gov/vuln/detail/CVE-2026-1225
- https://logback.qos.ch/news.html#1.5.25
- qos-ch/logback#997
- qos-ch/logback@1f97ae1
Published to the GitHub Advisory Database
Jan 22, 2026
Last updated
Jan 22, 2026