CVE-2026-105242
Published:October 06, 2026
Updated:October 11, 2026
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.
Affected Packages
log4net (DOT_NET):
Affected version(s) >=3.0.0.0 <3.5.0Fix Suggestion:
Update to version 3.5.0https://github.com/apache/logging-log4net.git (GITHUB):
Affected version(s) >=rel/3.0.0 <rel/3.5.0Fix Suggestion:
Update to version rel/3.5.0log4net (NUGET):
Affected version(s) >=3.0.0 <3.5.0Fix Suggestion:
Update to version 3.5.0Related Resources (8)
Do you need more information?
Contact UsCVSS v4
Base Score:
6.9
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
NONE
Vulnerable System Confidentiality
NONE
Vulnerable System Integrity
LOW
Vulnerable System Availability
NONE
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
5.3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
LOW
Availability
NONE
Weakness Type (CWE)
Improper Handling of Exceptional Conditions
EPSS
Base Score:
0.82