CVE-2026-105244
mediumpriority · track · 0EPSS 0.008 · 57 %ileDEUSEPSS · scored 2026-10-27
Improper Encoding or Escaping of Output vulnerability in the RemoteSyslogAppender of Apache log4net. Every character outside visible ASCII and space was removed from the record instead of being escaped, so non-ASCII text and control characters such as tabs disappeared without notice. A party whose data reaches a log message could make a distinct value look identical in the record, for example a user name holding a zero-width space logged as admin. Only applications that use RemoteSyslogAppender are affected. This issue affects Apache log4net: from 1.2.12 before 3.5.0. Users are recommended to upgrade to version 3.5.0, which fixes the issue.
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (3)
Products and version ranges known to be affected.
advisories (1)
Vendor and ecosystem advisories describing this.
- WID-SEC-W-2026-3772Apache log4net: Mehrere Schwachstellen ermöglichen Manipulation von DateienDeutsch2026-10-06csaf · cert_bundDE
Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in Apache log4net ausnutzen, um Dateien zu manipulieren.
sources
Which sources assert this record, and when.
references (4) nvd
External citations — patches, advisories, analysis.
- http://www.openwall.com/lists/oss-security/2026/10/07/19Mailing ListThird Party Advisory
- https://github.com/apache/logging-log4net/commit/77717061b20d4346b6c0ce6b54643d85fb348bc7Patch
- https://github.com/apache/logging-log4net/pull/315PatchVendor Advisory
- https://lists.apache.org/thread.html/q7649hhdodthoqw8jsjgtnb4m8qfy6d6Mailing ListVendor Advisory
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