{"id":"CVE-2026-105241","published":"2026-10-06T20:17:15.907","lastModified":"2026-10-09T15:29:42.560","description":"Improper Handling of Unicode Encoding vulnerability in the SmtpPickupDirAppender of Apache log4net.\n\nContent that the mail file writer cannot encode, such as an unpaired UTF-16 surrogate, made the write throw. Every buffered event in the batch was discarded, not only the one carrying the content, and a truncated mail could be left in the pickup directory. A party whose data reaches a log message could suppress the records of other events. Only applications that use SmtpPickupDirAppender are affected.\n\nThis issue affects Apache log4net: from 1.2.9 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-176"],"vendors":["apache"],"products":["log4net"],"references":[{"url":"https://github.com/apache/logging-log4net/commit/4d2e10f0908199604b4326f9df6d0b43b871e333","tags":["Patch"]},{"url":"https://github.com/apache/logging-log4net/pull/315","tags":["Patch"]},{"url":"https://lists.apache.org/thread.html/hg8dgh3oy8bp3dhb8nsygk9kw2o401ws","tags":["Mailing List","Vendor Advisory"]},{"url":"http://www.openwall.com/lists/oss-security/2026/10/07/15","tags":["Mailing List","Third Party Advisory"]}],"exploitRefs":[{"url":"https://github.com/apache/logging-log4net/commit/4d2e10f0908199604b4326f9df6d0b43b871e333","tags":["Patch"]},{"url":"https://github.com/apache/logging-log4net/pull/315","tags":["Patch"]}],"hasPoc":true,"ai":null}