CVE-2026-105242

EUVD-2026-93867
Improper Handling of Exceptional Conditions vulnerability in the aspnet-request pattern converter of Apache log4net.

Reading request parameters triggers ASP.NET request validation, so a request carrying content such as markup made the layout throw and the appender discarded the whole event. A sender could suppress the log record of their own request. Only applications on ASP.NET for .NET Framework whose layout uses %aspnet-request are affected.

This issue affects Apache log4net: from 1.2.11 before 3.5.0.

Users are recommended to upgrade to version 3.5.0, which fixes the issue.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
apacheCNA
5.3 MEDIUM
NETWORK
LOW
NONE
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Base Score
CVSS 3.x
EPSS Score
Percentile: Unknown
Early Detection
Affected products identified ahead of NVD analysis through intelligence sources.
VendorProductVersionSource
apachelog4net
1.2.11 ≤
𝑥
< 3.5.0
CNA
Common Weakness Enumeration
References
https://github.com/apache/logging-log4net/commit/145203420c579a703008b4b723b6a080757f4964
https://github.com/apache/logging-log4net/pull/316
https://lists.apache.org/thread.html/zg6dbqm4ztm7j3c21nfsqj0yxm5yrpdx