CVE-2026-105240

published 2026-10-06

CVE-2026-105240: Improper Neutralization of Null Byte or NUL Character vulnerability in the OutputDebugStringAppender of Apache log4net. A NUL character in logged content ended…

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 OutputDebugStringAppender of Apache log4net.

A NUL character in logged content ended the debug output record at that point, so everything the layout rendered after it, including exception text and trailing fields, was silently lost. A party whose data reaches a log message could hide the rest of that record. Only applications on Windows that use OutputDebugStringAppender 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 < 6046fe9d7f353b49fe995361c071ec2eea8f7ef6	6046fe9d7f353b49fe995361c071ec2eea8f7ef6
apache_software_foundation	apache_log4net	>= 1.2.9 < 3.5.0	3.5.0

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CWE-158