CVE-2026-105239

published 2026-10-06

CVE-2026-105239: Improper Neutralization of Null Byte or NUL Character vulnerability in the EventLogAppender of Apache log4net. A NUL character in logged content ended the…

Priority P4 31 medium 5.3 CVSS 3.1

AV N AC L PR N UI N S U C N I L A N

Improper Neutralization of Null Byte or NUL Character vulnerability in the EventLogAppender of Apache log4net.

A NUL character in logged content ended the Windows Event Log record at that point, so everything the layout rendered after it, including exception text and trailing fields, was silently not stored. A party whose data reaches a log message could hide the rest of that record. Only applications on Windows that use EventLogAppender 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.

Affected

3 ranges

Vendor	Product	Version range	Fixed in
apache	log4net	>= 1.2.9 < 3.5.0	3.5.0
apache_software_foundation	apache_log4net	>= 02e1e115435888485f2e28b414d267e39e799e07 < dc5855a0720c91590fd7a81d729ea01fdd69e000	dc5855a0720c91590fd7a81d729ea01fdd69e000
apache_software_foundation	apache_log4net	>= 1.2.9 < 3.5.0	3.5.0

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CWE-158