Bug 2547130 (CVE-2026-105241) - CVE-2026-105241 log4net: log4net: Log event suppression via improper Unicode handling in SmtpPickupDirAppender
Summary: CVE-2026-105241 log4net: log4net: Log event suppression via improper Unicode ...
Keywords:
Status: NEW
Alias: CVE-2026-105241
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: 2547383 2547384
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 20:02:13 UTC 
Improper Handling of Unicode Encoding vulnerability in the SmtpPickupDirAppender of Apache log4net.

Content that the mail file writer cannot encode, such as an unpaired UTF-16 surrogate, made the write throw. Every buffered event in the batch was discarded, not only the one carrying the content, and a truncated mail could be left in the pickup directory. A party whose data reaches a log message could suppress the records of other events. Only applications that use SmtpPickupDirAppender are affected.

This issue affects Apache log4net: from 1.2.9 before 3.5.0.

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