{"cve":"CVE-2026-105241","nvd":{"published":"2026-10-06T20:17:15.907","modified":"2026-10-09T15:29:42.560","status":"Analyzed","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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","score":5.3},"cwes":["CWE-176"],"references":["https://github.com/apache/logging-log4net/commit/4d2e10f0908199604b4326f9df6d0b43b871e333","https://github.com/apache/logging-log4net/pull/315","https://lists.apache.org/thread.html/hg8dgh3oy8bp3dhb8nsygk9kw2o401ws","http://www.openwall.com/lists/oss-security/2026/10/07/15"],"products":["apache:log4net"],"source":"nvd","synced_at":"2026-10-19T22:58:01.639778232+00:00"},"epss":{"cve":"CVE-2026-105241","score":0.00824,"percentile":0.57105,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}