CVE-2026-105241
Apache log4net: Unencodable content discards a whole SmtpPickupDirAppender batch
- State
- Published
- Severity
- 5.3 Medium
- Published
- Oct 6, 2026
- Updated
- Oct 7, 2026
- Reserved
- Oct 4, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 5.3 Medium | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N | apache |
Weaknesses
- CWE-176 Improper Handling of Unicode Encoding
Affected Products
| Product | Versions |
|---|---|
Apache log4netApache Software Foundation |
|
Apache log4netApache Software Foundation |
|
References
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