CVE-2026-105241

  1. OpenCVE
  2. Vulnerabilities (CVE)
  3. CVE-2026-105241
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.

5.3 /10

CVSS v3 : MEDIUM

V3 Legend

Vector :

Exploitability : 3.9 / Impact : 1.4

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact LOW

Availability Impact NONE

Scope UNCHANGED

References
Link Resource
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
Configurations

Configuration 1 (hide)

cpe:2.3:a:apache:log4net:*:*:*:*:*:*:*:*
History

09 Oct 2026, 15:29

Type Values Removed Values Added
CPE cpe:2.3:a:apache:log4net:*:*:*:*:*:*:*:*
References () https://github.com/apache/logging-log4net/commit/4d2e10f0908199604b4326f9df6d0b43b871e333 - () https://github.com/apache/logging-log4net/commit/4d2e10f0908199604b4326f9df6d0b43b871e333 - Patch
References () https://github.com/apache/logging-log4net/pull/315 - () https://github.com/apache/logging-log4net/pull/315 - Patch
References () https://lists.apache.org/thread.html/hg8dgh3oy8bp3dhb8nsygk9kw2o401ws - () https://lists.apache.org/thread.html/hg8dgh3oy8bp3dhb8nsygk9kw2o401ws - Mailing List, Vendor Advisory
References () http://www.openwall.com/lists/oss-security/2026/10/07/15 - () http://www.openwall.com/lists/oss-security/2026/10/07/15 - Mailing List, Third Party Advisory
First Time Apache log4net
Apache

07 Oct 2026, 07:16

Type Values Removed Values Added
References
  • () http://www.openwall.com/lists/oss-security/2026/10/07/15 -

06 Oct 2026, 20:17

Type Values Removed Values Added
New CVE
Information

Published : 2026-10-06 20:17

Updated : 2026-10-09 15:29

NVD link : CVE-2026-105241

Mitre link : CVE-2026-105241

CVE.ORG link : CVE-2026-105241

JSON object : View

Products Affected

apache

  • log4net
CWE
CWE-176

Improper Handling of Unicode Encoding