CVEvulnerability
CVE-2026-105241
5.3 MEDIUM
Official page ↗
- Status
- Analyzed
- Published
- 2026-10-06
- Last modified
- 2026-10-09
- Assigner
- [email protected]
- CVSS 3.1 ([email protected])
- 5.3 MEDIUM — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
- Weaknesses
- CWE-176
Description
Improper Handling of Unicode Encoding vulnerability in the SmtpPickupDirAppender of Apache log4net.
Content 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.
This issue affects Apache log4net: from 1.2.9 before 3.5.0.
Users are recommended to upgrade to version 3.5.0, which fixes the issue.
Affected configurations
• apache log4net (>= 1.2.9 < 3.5.0)
Related
Weakness · CWE (1)
- CWE-176 Improper Handling of Unicode Encoding weakness
References
- https://github.com/apache/logging-log4net/commit/4d2e10f0908199604b4326f9df6d0b43b871e333 Patch
- https://github.com/apache/logging-log4net/pull/315 Patch
- https://lists.apache.org/thread.html/hg8dgh3oy8bp3dhb8nsygk9kw2o401ws Mailing List, Vendor Advisory
- http://www.openwall.com/lists/oss-security/2026/10/07/15 Mailing List, Third Party Advisory