CVE-2026-1225: Malicious logback.xml configuration file allows instantiation of arbitrary classes

Published Jan 22, 2026
·
Updated

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.

Affected Software

3 affected componentsFixes available
maven/qos.ch/logback-core<=1.5.24
maven/ch.qos.logback:logback-core<1.5.25
1.5.25
IBM watsonx.data<=2.2- 2.3.1

Remediation

Information

Update to logback version 1.5.25 or later.

Event History

Jan 22, 2026
CVE Published
via MITRE·09:24 AM
Data Sourced
via MITRE·09:24 AM
RemedyDescriptionWeakness
Data Sourced
via NVD·10:16 AM
DescriptionSeverityWeakness
Advisory Published
via GitHub·12:31 PM
Data Sourced
via GitHub·12:31 PM
DescriptionWeaknessAffected Software
May 9, 2026
Data Sourced
via IBM·12:00 AM
DescriptionAffected Software

Parent advisories

This vulnerability appears in the following advisories.

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Frequently Asked Questions

1

What is the severity of CVE-2026-1225?

CVE-2026-1225 is considered a critical vulnerability as it allows attackers to instantiate arbitrary classes through malicious configuration.

2

How do I fix CVE-2026-1225?

To mitigate CVE-2026-1225, update your logback-core dependency to version 1.5.25 or later.

3

What are the potential impacts of exploiting CVE-2026-1225?

Exploiting CVE-2026-1225 can lead to remote code execution, unauthorized access, and manipulation of application behavior.

4

Which versions of logback-core are affected by CVE-2026-1225?

CVE-2026-1225 affects logback-core versions up to and including 1.5.24.

5

What type of applications are vulnerable to CVE-2026-1225?

Java applications using the affected versions of the QOS.CH logback-core library are vulnerable to CVE-2026-1225.

Contact

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