CVE-2026-105242
5.3 · MEDIUMImproper Handling of Exceptional Conditions vulnerability in the aspnet-request pattern converter of Apache log4net.
Overview
CVE-2026-105242 is a medium-severity vulnerability affecting apache log4net. It was published on October 6, 2026 and has a CVSS 3.1 base score of 5.3 (MEDIUM).
This vulnerability has a CVSS 3.1 base score of 5.3, rated MEDIUM. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
Technical 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.
Remediation
Check the references section for vendor advisories and patches from apache. Update log4net to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| apache | log4net | >= 1.2.11, < 3.5.0 | Affected |
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Frequently asked questions
What is CVE-2026-105242?
CVE-2026-105242 is a medium-severity vulnerability affecting apache log4net. It was published on October 6, 2026 and has a CVSS 3.1 base score of 5.3 (MEDIUM).
How severe is CVE-2026-105242?
This vulnerability has a CVSS 3.1 base score of 5.3, rated MEDIUM. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2026-105242?
Check the references section for vendor advisories and patches from apache. Update log4net to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-105242?
CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2026-105242 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.
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