CVE-2026-105243
mediumpriority · track · 0EPSS 0.008 · 57 %ileDEUSEPSS · scored 2026-10-27
Insufficient Logging vulnerability in the EventLogAppender of Apache log4net. Long messages were truncated to a fixed size that exceeds what the Windows Event Log accepts once the log and source names are counted, and the event log then stored nothing and reported nothing. A party whose data reaches a log message could suppress the whole record by making it long enough. Only applications on Windows that use EventLogAppender 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.
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/2026/10/07/17Mailing ListThird Party Advisory
- https://github.com/apache/logging-log4net/commit/28fbfb25678c48a8cc5bc9b94ead0dddfc39ffedPatch
- https://github.com/apache/logging-log4net/pull/315Patch
- https://lists.apache.org/thread.html/jr6fj5skv1vnjbc9jmt8bp151p8ow1rpMailing ListVendor Advisory
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