{"id":"CVE-2026-105241","state":"PUBLISHED","title":"Apache log4net: Unencodable content discards a whole SmtpPickupDirAppender batch","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.","publishedAt":"2026-10-06T19:49:03.994Z","updatedAt":"2026-10-07T14:45:58.074Z","severity":{"score":5.3,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","source":"apache"},"assigner":"apache","products":["Apache Software Foundation Apache log4net"],"affected":[{"vendor":"Apache Software Foundation","product":"Apache log4net","packageName":"log4net","packageURL":"pkg:nuget/log4net","defaultStatus":"unaffected","versions":[{"version":"1.2.9","status":"affected","lessThan":"3.5.0","versionType":"semver"}],"collectionURL":"https://nuget.org/packages"},{"vendor":"Apache Software Foundation","product":"Apache log4net","packageName":"log4net","packageURL":"pkg:nuget/log4net","defaultStatus":"unaffected","versions":[{"version":"02e1e115435888485f2e28b414d267e39e799e07","status":"affected","lessThan":"4d2e10f0908199604b4326f9df6d0b43b871e333","versionType":"git"}],"repo":"https://gitbox.apache.org/repos/asf/logging-log4net.git","collectionURL":"https://nuget.org/packages"}],"references":["https://github.com/apache/logging-log4net/pull/315","https://github.com/apache/logging-log4net/commit/4d2e10f0908199604b4326f9df6d0b43b871e333","https://lists.apache.org/thread.html/hg8dgh3oy8bp3dhb8nsygk9kw2o401ws","http://www.openwall.com/lists/oss-security/2026/10/07/15"],"weaknesses":["CWE-176"],"ingestedAt":"2026-10-29T20:10:23.711Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/105xxx/CVE-2026-105241.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-105241","state":"PUBLISHED","datePublished":"2026-10-06T19:49:03.994Z","dateUpdated":"2026-10-07T14:45:58.074Z","assignerShortName":"apache","assignerOrgId":"f0158376-9dc2-43b6-827c-5f631a4d8d09","dateReserved":"2026-10-04T16:20:44.036Z"},"containers":{"cna":{"title":"Apache log4net: Unencodable content discards a whole SmtpPickupDirAppender batch","descriptions":[{"lang":"en","value":"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. 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