{"id":"CVE-2026-105244","published":"2026-10-06T20:17:16.297","lastModified":"2026-10-09T15:18:44.677","description":"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 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.","cvssScore":5.3,"cvssSeverity":"MEDIUM","cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","cwes":["CWE-116"],"vendors":["apache"],"products":["log4net"],"references":[{"url":"https://github.com/apache/logging-log4net/commit/77717061b20d4346b6c0ce6b54643d85fb348bc7","tags":["Patch"]},{"url":"https://github.com/apache/logging-log4net/pull/315","tags":["Patch","Vendor Advisory"]},{"url":"https://lists.apache.org/thread.html/q7649hhdodthoqw8jsjgtnb4m8qfy6d6","tags":["Mailing List","Vendor Advisory"]},{"url":"http://www.openwall.com/lists/oss-security/2026/10/07/19","tags":["Mailing List","Third Party Advisory"]}],"exploitRefs":[{"url":"https://github.com/apache/logging-log4net/commit/77717061b20d4346b6c0ce6b54643d85fb348bc7","tags":["Patch"]},{"url":"https://github.com/apache/logging-log4net/pull/315","tags":["Patch","Vendor Advisory"]}],"hasPoc":true,"ai":null}