CVE-2023-6378

logback serialization vulnerability

A serialization vulnerability in logback receiver component part of logback allows an attacker to mount a Denial-Of-Service attack by sending poisoned data.

This is only exploitable if logback receiver component is deployed. See https://logback.qos.ch/manual/receivers.html

Untrusted serialized data is processed by a deserializer that can instantiate arbitrary objects or execute code as a side effect. Typical impact: arbitrary code execution or logic abuse.

CVE-2023-6378 has a CVSS score of 7.1 (High). The vector is requires local access, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.4.12, 1.3.12, 1.2.13); upgrading removes the vulnerable code path.

Kodem intelligence

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1. What is CVE-2023-6378? CVE-2023-6378 is a high-severity insecure deserialization vulnerability in ch.qos.logback:logback-classic (maven), affecting versions >= 1.4.0, < 1.4.12. It is fixed in 1.4.12, 1.3.12, 1.2.13. Untrusted serialized data is processed by a deserializer that can instantiate arbitrary objects or execute code as a side effect.
2. How severe is CVE-2023-6378? CVE-2023-6378 has a CVSS score of 7.1 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which packages are affected by CVE-2023-6378?
   • ch.qos.logback:logback-classic (maven) (versions >= 1.4.0, < 1.4.12)
   • ch.qos.logback:logback-core (maven) (versions >= 1.4.0, < 1.4.12)
4. Is there a fix for CVE-2023-6378? Yes. CVE-2023-6378 is fixed in 1.4.12, 1.3.12, 1.2.13. Upgrade to this version or later.
5. Is CVE-2023-6378 exploitable, and should I be worried? Whether CVE-2023-6378 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
6. What actually determines whether CVE-2023-6378 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.
7. How do I fix CVE-2023-6378?
   • Upgrade ch.qos.logback:logback-classic to 1.4.12 or later
   • Upgrade ch.qos.logback:logback-core to 1.4.12 or later
   • Upgrade ch.qos.logback:logback-classic to 1.3.12 or later
   • Upgrade ch.qos.logback:logback-core to 1.3.12 or later
   • Upgrade ch.qos.logback:logback-core to 1.2.13 or later
   • Upgrade ch.qos.logback:logback-classic to 1.2.13 or later

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