5.3
Medium
CVE-2026-105243 Insufficient Logging vulnerability in the EventLogAppender of Apache log4net
Description
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.
Affected products and versions
| Product | Affected versions | Fixed in |
|---|---|---|
| Apache Log4net | Versions not published |
Other CVEs of Apache Log4net
The 7 CVEs of Apache Log4net →
CVE-2026-105244
Improper Encoding or Escaping of Output vulnerability in the RemoteSyslogAppender of Apache log4net
5.3
Medium
CVE-2026-105242
Improper Handling of Exceptional Conditions vulnerability in the aspnet-request pattern converter of Apache log4net
5.3
Medium
CVE-2026-105241
Improper Handling of Unicode Encoding vulnerability in the SmtpPickupDirAppender of Apache log4net
5.3
Medium
CVE-2026-105240
Improper Neutralization of Null Byte or NUL Character vulnerability in the OutputDebugStringAppender of Apache log4net
5.3
Medium