ch.qos.logback:logback-classic 1.3.0-beta0

Direct Vulnerabilities

Known vulnerabilities in the ch.qos.logback:logback-classic package. This does not include vulnerabilities belonging to this package’s dependencies.

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Vulnerability	Vulnerable Version
M Directory Traversal ch.qos.logback:logback-classic is a reliable, generic, fast and flexible logging library for Java. Affected versions of this package are vulnerable to Directory Traversal via unsanitized input in the `MDCDiscriminator` process. An attacker can create or append log files outside the intended directory by supplying crafted values, such as through HTTP headers, that influence the log file path. This is only exploitable if `SiftingAppender` is active and unsanitized data is used by `MDCDiscriminator`. How to fix Directory Traversal? Upgrade `ch.qos.logback:logback-classic` to version 1.6.5 or higher.	[0.9.14,1.6.5)
M Directory Traversal ch.qos.logback:logback-classic is a reliable, generic, fast and flexible logging library for Java. Affected versions of this package are vulnerable to Directory Traversal in `MDCBasedDiscriminator`, used by `SiftingAppender`, which takes an MDC value as the discriminating key without removing path separators, so the value reaches the nested `FileAppender` path unsanitized. An attacker can direct log output to a file outside the intended directory by supplying an MDC value containing `/` or `\` path segments. This requires a configuration whose `SiftingAppender` discriminates on MDC and whose nested `FileAppender` interpolates the discriminating key into its file path, with that MDC value populated from attacker-influenced input. Note: This is a bypass of the fix for the vulnerability described in CVE-2025-11226. How to fix Directory Traversal? Upgrade `ch.qos.logback:logback-classic` to version 1.6.3 or higher.	[0.9.14,1.6.3)
M Deserialization of Untrusted Data ch.qos.logback:logback-classic is a reliable, generic, fast and flexible logging library for Java. Affected versions of this package are vulnerable to Deserialization of Untrusted Data in `HardenedObjectInputStream`, whose `resolveClass` allowlist admitted any class whose name starts with `java.lang` or `java.util` rather than matching specific authorized classes. An attacker can instantiate dangerous classes such as `java.lang.ProcessBuilder` during deserialization, reaching remote code execution through a gadget chain, by delivering a malicious serialized object to a logback component that deserializes it, such as its socket receiver for serialized logging events (`SocketNode`). Exploitation requires the application to deserialize attacker-controlled serialized data through logback, in practice via its socket-based receiver, together with a usable gadget class on the classpath. How to fix Deserialization of Untrusted Data? Upgrade `ch.qos.logback:logback-classic` to version 1.5.33 or higher.	[,1.5.33)
M Improper Neutralization of Special Elements ch.qos.logback:logback-classic is a reliable, generic, fast and flexible logging library for Java. Affected versions of this package are vulnerable to Improper Neutralization of Special Elements via the `JaninoEventEvaluator` extension. An attacker can execute arbitrary code by compromising an existing logback configuration file or injecting an environment variable before program execution. How to fix Improper Neutralization of Special Elements? Upgrade `ch.qos.logback:logback-classic` to version 1.3.15, 1.5.13 or higher.	[,1.3.15)[1.4.0,1.5.13)
H Denial of Service (DoS) ch.qos.logback:logback-classic is a reliable, generic, fast and flexible logging library for Java. Affected versions of this package are vulnerable to Denial of Service (DoS). An attacker can mount a denial-of-service attack by sending poisoned data. This is only exploitable if logback receiver component is deployed. How to fix Denial of Service (DoS)? Upgrade `ch.qos.logback:logback-classic` to version 1.2.13, 1.3.12, 1.4.12 or higher.	[,1.2.13)[1.3.0-alpha0,1.3.12)[1.4.0,1.4.12)

Vulnerability

Vulnerable Version

Directory Traversal

ch.qos.logback:logback-classic is a reliable, generic, fast and flexible logging library for Java.

Affected versions of this package are vulnerable to Directory Traversal via unsanitized input in the MDCDiscriminator process. An attacker can create or append log files outside the intended directory by supplying crafted values, such as through HTTP headers, that influence the log file path. This is only exploitable if SiftingAppender is active and unsanitized data is used by MDCDiscriminator.

How to fix Directory Traversal?

Upgrade ch.qos.logback:logback-classic to version 1.6.5 or higher.

[0.9.14,1.6.5)

Directory Traversal

ch.qos.logback:logback-classic is a reliable, generic, fast and flexible logging library for Java.

Affected versions of this package are vulnerable to Directory Traversal in MDCBasedDiscriminator, used by SiftingAppender, which takes an MDC value as the discriminating key without removing path separators, so the value reaches the nested FileAppender path unsanitized. An attacker can direct log output to a file outside the intended directory by supplying an MDC value containing / or \ path segments. This requires a configuration whose SiftingAppender discriminates on MDC and whose nested FileAppender interpolates the discriminating key into its file path, with that MDC value populated from attacker-influenced input.

Note: This is a bypass of the fix for the vulnerability described in CVE-2025-11226.

How to fix Directory Traversal?

Upgrade ch.qos.logback:logback-classic to version 1.6.3 or higher.

[0.9.14,1.6.3)

Deserialization of Untrusted Data

ch.qos.logback:logback-classic is a reliable, generic, fast and flexible logging library for Java.

Affected versions of this package are vulnerable to Deserialization of Untrusted Data in HardenedObjectInputStream, whose resolveClass allowlist admitted any class whose name starts with java.lang or java.util rather than matching specific authorized classes. An attacker can instantiate dangerous classes such as java.lang.ProcessBuilder during deserialization, reaching remote code execution through a gadget chain, by delivering a malicious serialized object to a logback component that deserializes it, such as its socket receiver for serialized logging events (SocketNode). Exploitation requires the application to deserialize attacker-controlled serialized data through logback, in practice via its socket-based receiver, together with a usable gadget class on the classpath.

How to fix Deserialization of Untrusted Data?

Upgrade ch.qos.logback:logback-classic to version 1.5.33 or higher.

[,1.5.33)

Improper Neutralization of Special Elements

ch.qos.logback:logback-classic is a reliable, generic, fast and flexible logging library for Java.

Affected versions of this package are vulnerable to Improper Neutralization of Special Elements via the JaninoEventEvaluator extension. An attacker can execute arbitrary code by compromising an existing logback configuration file or injecting an environment variable before program execution.

How to fix Improper Neutralization of Special Elements?

Upgrade ch.qos.logback:logback-classic to version 1.3.15, 1.5.13 or higher.

[,1.3.15)[1.4.0,1.5.13)

Denial of Service (DoS)

ch.qos.logback:logback-classic is a reliable, generic, fast and flexible logging library for Java.

Affected versions of this package are vulnerable to Denial of Service (DoS). An attacker can mount a denial-of-service attack by sending poisoned data. This is only exploitable if logback receiver component is deployed.

How to fix Denial of Service (DoS)?

Upgrade ch.qos.logback:logback-classic to version 1.2.13, 1.3.12, 1.4.12 or higher.

[,1.2.13)[1.3.0-alpha0,1.3.12)[1.4.0,1.4.12)

ch.qos.logback:logback-classic@1.3.0-beta0

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Direct Vulnerabilities

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