{"id":"CVE-2026-105242","title":"Improper Handling of Exceptional Conditions vulnerability in the aspnet-request pattern converter of Apache log4net.\n\nReading request parameters triggers ASP.NET request validation, so a request carrying content such as markup made the l…","summary":"Improper Handling of Exceptional Conditions vulnerability in the aspnet-request pattern converter of Apache log4net.\n\nReading request parameters triggers ASP.NET request validation, so a request carrying content such as markup made the l…","severity":"medium","cvss":5.3,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","cwe":["CWE-755"],"vendor":"apache","product":"log4net","affected":["log4net >= 1.2.11, < 3.5.0"],"patched":["log4net 3.5.0"],"published":"2026-10-06","updated":"2026-10-09","sourceUpdated":"2026-10-09T15:28:34.500","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-105242","references":[{"url":"https://github.com/apache/logging-log4net/commit/145203420c579a703008b4b723b6a080757f4964","label":"security@apache.org"},{"url":"https://github.com/apache/logging-log4net/pull/316","label":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/zg6dbqm4ztm7j3c21nfsqj0yxm5yrpdx","label":"security@apache.org"},{"url":"http://www.openwall.com/lists/oss-security/2026/10/07/16","label":"af854a3a-2127-422b-91ae-364da2661108"}],"tags":["nvd","cve.org"],"epss":0.00823,"epssPercentile":0.57157,"ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"partial","timestamp":"2026-10-07T14:48:50.404406Z"},"ingestedAt":"2026-10-06T20:16:42.477Z","slug":"CVE-2026-105242","body":"## Overview\n\nImproper Handling of Exceptional Conditions vulnerability in the aspnet-request pattern converter of Apache log4net.\n\nReading 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.\n\nThis issue affects Apache log4net: from 1.2.11 before 3.5.0.\n\nUsers are recommended to upgrade to version 3.5.0, which fixes the issue.\n\n## Affected\n\n- `log4net >= 1.2.11, < 3.5.0`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `log4net 3.5.0`","depth":"sunlit","depthScore":29,"depthScoreParts":{"impact":29.2,"likelihood":0.2,"exploitation":0,"ransomware":0},"changes":[]}