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.
History

Fri, 09 Oct 2026 15:45:00 +0000

Type Values Removed Values Added
CPEs cpe:2.3:a:apache:log4net:*:*:*:*:*:*:*:*

Wed, 07 Oct 2026 15:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Wed, 07 Oct 2026 07:30:00 +0000

Type Values Removed Values Added
References

Tue, 06 Oct 2026 23:15:00 +0000

Type Values Removed Values Added
First Time appeared Apache
Apache log4net
Vendors & Products Apache
Apache log4net

Tue, 06 Oct 2026 20:00:00 +0000

Type Values Removed Values Added
Description 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.
Title Apache log4net: Request validation failure drops the event in the aspnet-request converter
Weaknesses CWE-755
References
Metrics cvssV3_1

{'score': 5.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: apache

Published: 2026-10-06T19:50:19.075Z

Updated: 2026-10-07T14:49:06.441Z

Reserved: 2026-10-04T16:21:12.546Z

Link: CVE-2026-105242

cve-icon Vulnrichment

Updated: 2026-10-07T06:11:58.703Z

cve-icon NVD

Status : Analyzed

Published: 2026-10-06T20:17:16.037

Modified: 2026-10-09T15:28:34.500

Link: CVE-2026-105242

cve-icon Redhat

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