Summary
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.
Impact
The application does not adequately validate input before processing it, allowing unexpected values to reach sensitive code paths. Typical impact: varies by context: data corruption, logic bypass, or denial of service.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is CVE-2026-1225? CVE-2026-1225 is a low-severity improper input validation vulnerability in ch.qos.logback:logback-core (maven), affecting versions < 1.5.25. It is fixed in 1.5.25. The application does not adequately validate input before processing it, allowing unexpected values to reach sensitive code paths.
- Which versions of ch.qos.logback:logback-core are affected by CVE-2026-1225? ch.qos.logback:logback-core (maven) versions < 1.5.25 is affected.
- Is there a fix for CVE-2026-1225? Yes. CVE-2026-1225 is fixed in 1.5.25. Upgrade to this version or later.
- Is CVE-2026-1225 exploitable, and should I be worried? Whether CVE-2026-1225 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-1225 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-1225? Upgrade
ch.qos.logback:logback-coreto 1.5.25 or later.