CVE-2026-105244

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 whos...

CVE-2026-105242

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 appender discarded the whole event. A...

CVE-2026-105243

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...

CVE-2026-105239

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 text and trailing fields, was silently...

CVE-2026-105240

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 exception text and trailing fields, was...

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,...

CVE-2026-105244 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 disappeared without notice. A party whos...

EUVD-2026-93870

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 whos...

CVE-2026-105244

The Apache log4net logging framework (versions 1.2.12 before 3.5.0 ) contains an Improper Encoding or Escaping of Output vulnerability in the RemoteSyslogAppender component. Instead of escaping non-ASCII characters and control characters (like tabs), the appender silently deletes them. This allow...

CVE-2026-105243

The Apache log4net logging framework (versions 1.2.9 before 3.5.0 ) contains an Insufficient Logging vulnerability in the EventLogAppender component on Windows. The root cause is that long messages are truncated to a fixed size that exceeds the Windows Event Log capacity once log and source names...

EUVD-2026-93869

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...

CVE-2026-105243 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 reported nothing. A party whose data...

EUVD-2026-93867

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 appender discarded the whole event. A...

CVE-2026-105242

The Apache log4net logging framework (versions 1.2.11 through 3.5.0 ) is vulnerable to an Improper Handling of Exceptional Conditions (CWE-755) in the aspnet-request pattern converter. When reading request parameters, certain content—such as markup—triggers ASP.NET request validation , causing th...

CVE-2026-105242 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 appender discarded the whole event. A...

CVE-2026-105241

The Apache log4net logging framework (versions 1.2.9 before 3.5.0 ) is vulnerable to an Improper Handling of Unicode Encoding issue within the SmtpPickupDirAppender component. If the mail file writer encounters content it cannot encode, such as an unpaired UTF-16 surrogate , it causes the write o...

EUVD-2026-93866

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,...

CVE-2026-105241 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, not only the one carrying the content,...

CVE-2026-105240

The Apache log4net logging framework (versions 1.2.9 before 3.5.0) is vulnerable to an Improper Neutralization of Null Byte or NUL Character (CWE-158) within the OutputDebugStringAppender . On Windows systems, a NUL character in logged content causes the debug output record to truncate prematurel...

EUVD-2026-93864

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 exception text and trailing fields, was...