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Product · Apache Software Foundation

Apache Log4net

7 known vulnerabilities.

Apache Log4net at a glance

Last 12 months
7
Critical · all time
0
Exploited · all time
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Public exploit · all time
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New vulnerabilities per month · last 12 months
0 5 10 December 2025: 0 vulnerabilities Dec 2025 January 2026: 0 vulnerabilities February 2026: 0 vulnerabilities March 2026: 0 vulnerabilities Mar April 2026: 1 vulnerability May 2026: 0 vulnerabilities June 2026: 0 vulnerabilities Jun July 2026: 0 vulnerabilities August 2026: 0 vulnerabilities September 2026: 0 vulnerabilities Sep October 2026: 6 vulnerabilities November 2026: 0 vulnerabilities
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7 results · Feed

  • Medium 5.3

    Apache log4net: RemoteSyslogAppender silently deletes non-ASCII content

    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 di…

  • Medium 5.3

    Apache log4net: Oversize EventLogAppender record silently discarded

    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 rep…

  • Medium 5.3

    Apache log4net: Request validation failure drops the event in the aspnet-request converter

    Improper Handling of Exceptional Conditions vulnerability in the aspnet-request pattern converter of Apache log4net. Reading request parameters triggers ASP.NET request validation, so a request carrying content such as markup made the layout throw and the app…

  • Medium 5.3

    Apache log4net: Unencodable content discards a whole SmtpPickupDirAppender batch

    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, n…

  • Medium 5.3

    Apache log4net: NUL character truncates OutputDebugStringAppender records

    Improper Neutralization of Null Byte or NUL Character vulnerability in the OutputDebugStringAppender of Apache log4net. A NUL character in logged content ended the debug output record at that point, so everything the layout rendered after it, including except…

  • Medium 5.3

    Apache log4net: NUL character truncates EventLogAppender records

    Improper Neutralization of Null Byte or NUL Character vulnerability in the EventLogAppender of Apache log4net. A NUL character in logged content ended the Windows Event Log record at that point, so everything the layout rendered after it, including exception …

  • Medium 6.3

    Apache Log4net: Silent log event loss in XmlLayout and XmlLayoutSchemaLog4J due to unescaped XML 1.0 forbidden characters

    Apache Log4net's XmlLayout https://logging.apache.org/log4net/manual/configuration/layouts.html#layout-list and XmlLayoutSchemaLog4J https://logging.apache.org/log4net/manual/configuration/layouts.html#layout-list , in versions before 3.3.0, fail to sanitize …