Riskcovery

CVE-2026-105244

Apache log4net: RemoteSyslogAppender silently deletes non-ASCII content

State
Published
Severity
5.3 Medium
Published
Oct 6, 2026
Updated
Oct 7, 2026
Reserved
Oct 4, 2026

Read the record on cve.org

Description

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.

Scores

CVSSScoreVectorSource
3.15.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:Napache

Weaknesses

  • CWE-116 Improper Encoding or Escaping of Output

Affected Products

ProductVersions
Apache log4netApache Software Foundation
  • 1.2.12 to before 3.5.0Affected
Apache log4netApache Software Foundation
  • 56a2e146e21ff4737e1ff3ec308810e667873947 to before 77717061b20d4346b6c0ce6b54643d85fb348bc7Affected

References

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