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.
Metrics
Affected Vendors & Products
References
History
Fri, 09 Oct 2026 15:45:00 +0000
| Type | Values Removed | Values Added |
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| CPEs | cpe:2.3:a:apache:log4net:*:*:*:*:*:*:*:* |
Wed, 07 Oct 2026 15:30:00 +0000
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|---|---|---|
| Metrics |
ssvc
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Wed, 07 Oct 2026 07:30:00 +0000
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| References |
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Wed, 07 Oct 2026 01:15:00 +0000
| Type | Values Removed | Values Added |
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| First Time appeared |
Apache
Apache log4net |
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| Vendors & Products |
Apache
Apache log4net |
Tue, 06 Oct 2026 20:00:00 +0000
| Type | Values Removed | Values Added |
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| 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. | |
| Title | Apache log4net: Unencodable content discards a whole SmtpPickupDirAppender batch | |
| Weaknesses | CWE-176 | |
| References |
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| Metrics |
cvssV3_1
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Status: PUBLISHED
Assigner: apache
Published: 2026-10-06T19:49:03.994Z
Updated: 2026-10-07T14:45:58.074Z
Reserved: 2026-10-04T16:20:44.036Z
Link: CVE-2026-105241
Updated: 2026-10-07T06:11:57.596Z
Status : Analyzed
Published: 2026-10-06T20:17:15.907
Modified: 2026-10-09T15:29:42.560
Link: CVE-2026-105241
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