GHSA-H383-GMXW-35V2 Apache Log4j 1 to Log4j 2 bridge: silent log event loss in Log4j1XmlLayout due to unescaped XML 1.0 forbidden characters

The Log4j1XmlLayout from the Apache Log4j 1-to-Log4j 2 bridge fails to escape characters forbidden by the XML 1.0 standard, producing malformed XML output. Conforming XML parsers are required to reject documents containing such characters with a fatal error, which may cause downstream log...

EUVD-2026-21488

Apache Log4net's XmlLayout https://logging.apache.org/log4net/manual/configuration/layouts.htmllayout-list and XmlLayoutSchemaLog4J https://logging.apache.org/log4net/manual/configuration/layouts.htmllayout-list , in versions before 3.3.0, fail to sanitize characters forbidden by the XML 1.0...

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.htmllayout-list and XmlLayoutSchemaLog4J https://logging.apache.org/log4net/manual/configuration/layouts.htmllayout-list , in versions before 3.3.0, fail to sanitize characters forbidden by the XML 1.0...

EUVD-2026-21410

Apache Log4j Core's XmlLayout https://logging.apache.org/log4j/2.x/manual/layouts.htmlXmlLayout , in versions up to and including 2.25.3, fails to sanitize characters forbidden by the XML 1.0 specification https://www.w3.org/TR/xml/charsets producing invalid XML output whenever a log message or M...

Apache Log4j Core: Silent log event loss in XmlLayout due to unescaped XML 1.0 forbidden characters

Apache Log4j Core's XmlLayout, in versions up to and including 2.25.3, fails to sanitize characters forbidden by the XML 1.0 specification, producing invalid XML output whenever a log message or MDC value contains such characters. The impact depends on the StAX implementation in use: JRE built-in...

Improper Encoding or Escaping of Output

Overview org.apache.logging.log4j:log4j-core is a logging library for Java. Affected versions of this package are vulnerable to Improper Encoding or Escaping of Output in the Log4j1XmlLayout plugin. An attacker can cause log events to be silently lost or downstream log processing systems to drop ...

CVE-2026-40021

Apache Log4net's XmlLayout https://logging.apache.org/log4net/manual/configuration/layouts.htmllayout-list and XmlLayoutSchemaLog4J https://logging.apache.org/log4net/manual/configuration/layouts.htmllayout-list , in versions before 3.3.0, fail to sanitize characters forbidden by the XML 1.0...

DEBIAN-CVE-2026-40021

Apache Log4net's XmlLayout https://logging.apache.org/log4net/manual/configuration/layouts.htmllayout-list and XmlLayoutSchemaLog4J https://logging.apache.org/log4net/manual/configuration/layouts.htmllayout-list , in versions before 3.3.0, fail to sanitize characters forbidden by the XML 1.0...

CVE-2026-40023

Apache Log4cxx's XMLLayout https://logging.apache.org/log4cxx/1.7.0/classlog4cxx11xml11XMLLayout.html , in versions before 1.7.0, fails to sanitize characters forbidden by the XML 1.0 specification https://www.w3.org/TR/xml/charsets in log messages, NDC, and MDC property keys and values, producin...

DEBIAN-CVE-2026-40023

Apache Log4cxx's XMLLayout https://logging.apache.org/log4cxx/1.7.0/classlog4cxx11xml11XMLLayout.html , in versions before 1.7.0, fails to sanitize characters forbidden by the XML 1.0 specification https://www.w3.org/TR/xml/charsets in log messages, NDC, and MDC property keys and values, producin...

CVE-2026-34479

The Log4j1XmlLayout from the Apache Log4j 1-to-Log4j 2 bridge fails to escape characters forbidden by the XML 1.0 standard, producing malformed XML output. Conforming XML parsers are required to reject documents containing such characters with a fatal error, which may cause downstream log...

DEBIAN-CVE-2026-34480

Apache Log4j Core's XmlLayout https://logging.apache.org/log4j/2.x/manual/layouts.htmlXmlLayout , in versions up to and including 2.25.3, fails to sanitize characters forbidden by the XML 1.0 specification https://www.w3.org/TR/xml/charsets producing invalid XML output whenever a log message or M...

CVE-2026-40021

Apache Log4net's XmlLayout https://logging.apache.org/log4net/manual/configuration/layouts.htmllayout-list and XmlLayoutSchemaLog4J https://logging.apache.org/log4net/manual/configuration/layouts.htmllayout-list , in versions before 3.3.0, fail to sanitize characters forbidden by the XML 1.0...

CVE-2026-40023

Apache Log4cxx's XMLLayout https://logging.apache.org/log4cxx/1.7.0/classlog4cxx11xml11XMLLayout.html , in versions before 1.7.0, fails to sanitize characters forbidden by the XML 1.0 specification https://www.w3.org/TR/xml/charsets in log messages, NDC, and MDC property keys and values, producin...

UBUNTU-CVE-2026-34480

Apache Log4j Core's XmlLayout https://logging.apache.org/log4j/2.x/manual/layouts.htmlXmlLayout , in versions up to and including 2.25.3, fails to sanitize characters forbidden by the XML 1.0 specification https://www.w3.org/TR/xml/charsets producing invalid XML output whenever a log message or M...

UBUNTU-CVE-2026-40021

Apache Log4net's XmlLayout https://logging.apache.org/log4net/manual/configuration/layouts.htmllayout-list and XmlLayoutSchemaLog4J https://logging.apache.org/log4net/manual/configuration/layouts.htmllayout-list , in versions before 3.3.0, fail to sanitize characters forbidden by the XML 1.0...

UBUNTU-CVE-2026-34479

The Log4j1XmlLayout from the Apache Log4j 1-to-Log4j 2 bridge fails to escape characters forbidden by the XML 1.0 standard, producing malformed XML output. Conforming XML parsers are required to reject documents containing such characters with a fatal error, which may cause downstream log...

UBUNTU-CVE-2026-40023

Apache Log4cxx's XMLLayout https://logging.apache.org/log4cxx/1.7.0/classlog4cxx11xml11XMLLayout.html , in versions before 1.7.0, fails to sanitize characters forbidden by the XML 1.0 specification https://www.w3.org/TR/xml/charsets in log messages, NDC, and MDC property keys and values, producin...

CVE-2026-40023 Apache Log4cxx, Apache Log4cxx (Conan), Apache Log4cxx (Brew): Silent log event loss in XMLLayout due to unescaped XML 1.0 forbidden characters

Apache Log4cxx's XMLLayout https://logging.apache.org/log4cxx/1.7.0/classlog4cxx11xml11XMLLayout.html , in versions before 1.7.0, fails to sanitize characters forbidden by the XML 1.0 specification https://www.w3.org/TR/xml/charsets in log messages, NDC, and MDC property keys and values, producin...

CVE-2026-40023 Apache Log4cxx, Apache Log4cxx (Conan), Apache Log4cxx (Brew): Silent log event loss in XMLLayout due to unescaped XML 1.0 forbidden characters

Apache Log4cxx's XMLLayout https://logging.apache.org/log4cxx/1.7.0/classlog4cxx11xml11XMLLayout.html , in versions before 1.7.0, fails to sanitize characters forbidden by the XML 1.0 specification https://www.w3.org/TR/xml/charsets in log messages, NDC, and MDC property keys and values, producin...