{"id":"CVE-2026-105244","title":"Improper Encoding or Escaping of Output vulnerability in the RemoteSyslogAppender of Apache log4net.\n\nEvery character outside visible ASCII and space was removed from the record instead of being escaped, so non-ASCII text and control cha…","summary":"Improper Encoding or Escaping of Output vulnerability in the RemoteSyslogAppender of Apache log4net.\n\nEvery character outside visible ASCII and space was removed from the record instead of being escaped, so non-ASCII text and control cha…","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-116"],"vendor":"Apache Software Foundation","product":"log4net","affected":["log4net >= 1.2.12 < 3.5.0","log4net >= 56a2e146e21ff4737e1ff3ec308810e667873947 < 77717061b20d4346b6c0ce6b54643d85fb348bc7"],"published":"2026-10-06","updated":"2026-10-06","sourceUpdated":"2026-10-06T20:17:16.297","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-105244","references":[{"url":"https://github.com/apache/logging-log4net/commit/77717061b20d4346b6c0ce6b54643d85fb348bc7","label":"security@apache.org"},{"url":"https://github.com/apache/logging-log4net/pull/315","label":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/q7649hhdodthoqw8jsjgtnb4m8qfy6d6","label":"security@apache.org"}],"tags":["nvd","cve.org"],"ingestedAt":"2026-10-06T20:16:42.474Z","slug":"CVE-2026-105244","body":"## Overview\n\nImproper Encoding or Escaping of Output vulnerability in the RemoteSyslogAppender of Apache log4net.\n\nEvery character outside visible ASCII and space was removed from the record instead of being escaped, so non-ASCII text and control characters such as tabs disappeared without notice. A party whose data reaches a log message could make a distinct value look identical in the record, for example a user name holding a zero-width space logged as admin. Only applications that use RemoteSyslogAppender are affected.\n\nThis issue affects Apache log4net: from 1.2.12 before 3.5.0.\n\nUsers are recommended to upgrade to version 3.5.0, which fixes the issue.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":29,"depthScoreParts":{"impact":29.2,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}