Bug 2545184 (CVE-2026-104721) - CVE-2026-104721 ch.qos.logback/logback-classic: logback-classic: Arbitrary file write via path traversal in MDC discriminator
Summary: CVE-2026-104721 ch.qos.logback/logback-classic: logback-classic: Arbitrary fi...
Keywords:
Status: NEW
Alias: CVE-2026-104721
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-10-02 13:33 UTC by OSIDB Bzimport
Modified: 2026-10-02 17:48 UTC (History)
52 users (show)

Fixed In Version:
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Description OSIDB Bzimport 2026-10-02 13:33:16 UTC 
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.
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