CVE-2026-105240
Description
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.
How to fix
- apache log4net3.5.0 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| apache log4net | 1.2.9 ≤ v < 3.5.0 | 3.5.0 |
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