Bug 2547134 (CVE-2026-105242) - CVE-2026-105242 log4net: log4net: Audit log suppression via crafted request parameters
Summary: CVE-2026-105242 log4net: log4net: Audit log suppression via crafted request p...
Keywords:
Status: NEW
Alias: CVE-2026-105242
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On: 2547385 2547386
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-10-06 20:02 UTC by OSIDB Bzimport
Modified: 2026-10-07 10:42 UTC (History)
0 users

Fixed In Version:
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Description OSIDB Bzimport 2026-10-06 20:02:28 UTC 
Improper Handling of Exceptional Conditions vulnerability in the aspnet-request pattern converter of Apache log4net.

Reading request parameters triggers ASP.NET request validation, so a request carrying content such as markup made the layout throw and the appender discarded the whole event. A sender could suppress the log record of their own request. Only applications on ASP.NET for .NET Framework whose layout uses %aspnet-request are affected.

This issue affects Apache log4net: from 1.2.11 before 3.5.0.

Users are recommended to upgrade to version 3.5.0, which fixes the issue.
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