RHLW-2026-4f8afe0cda7c5f03: Lightwell Security Advisory: logback-classic 1.5.16.rhlw-00003

Red Hat Lightwell has released ch.qos.logback:logback-classic 1.5.16.rhlw-00003 with backported fixes for CVE-2026-104721 and CVE-2026-19880.

CVE-2026-104721: Path-traversal vulnerability in QOS.CH Sarl Logback-classic on Java (logback-classic module) allows path-traversal vulnerability. More specifically, an MDC-based discriminator value flows unsanitized into a nested FileAppender path, letting an attacker who influences that MDC value (e.g. via an HTTP header) create and append log files outside the intended directory.

This issue affects Logback-classic: from 0.9.14 through 1.6.4.  This vulnerability is similar to CVE-2026-19880 but involves other attack techniques.

CVE-2026-19880: Path-traversal vulnerability in QOS.CH Sarl Logback-classic on Java (logback-classic module) allows path-traversal vulnerability. More specifically, an MDC-based discriminator value flows unsanitized into a nested FileAppender path, letting an attacker who influences that MDC value (e.g. via an HTTP header) create and append log files outside the intended directory.

This issue affects Logback-classic: from 0.9.14 through 1.6.2.

This patched artifact is a drop-in replacement for ch.qos.logback:logback-classic 1.5.16 from Maven Central.