CVE-2026-105242 MEDIUM

CVE-2026-105242: Apache log4net: Request validation failure drops the event in the aspnet-request converter

Vendor Apache Software Foundation
Product Apache log4net
Weakness CWE-755
Published October 6, 2026
Last update October 6, 2026
View on NVD All CVEs

CVSS base score

5.3/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality None
Integrity Low

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

October 6, 2026 CVE published