Bug 2547129 (CVE-2026-105244) - CVE-2026-105244 log4net: log4net: Log manipulation via improper character escaping in RemoteSyslogAppender
Summary: CVE-2026-105244 log4net: log4net: Log manipulation via improper character esc...
Keywords:
Status: NEW
Alias: CVE-2026-105244
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: 2547387 2547388
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-10-06 20:02 UTC by OSIDB Bzimport
Modified: 2026-10-07 10:43 UTC (History)
0 users

Fixed In Version:
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Description OSIDB Bzimport 2026-10-06 20:02:09 UTC 
Improper Encoding or Escaping of Output vulnerability in the RemoteSyslogAppender of Apache log4net.

Every character outside visible ASCII and space was removed from the record instead of being escaped, so non-ASCII text and control characters such as tabs disappeared without notice. A party whose data reaches a log message could make a distinct value look identical in the record, for example a user name holding a zero-width space logged as admin. Only applications that use RemoteSyslogAppender are affected.

This issue affects Apache log4net: from 1.2.12 before 3.5.0.

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