The vulnerability of the XmlLayout() function in the Apache Log4j Core library allows attackers to compromise the integrity of the protected information.

The vulnerability of the XmlLayout function in the Apache Log4j Core logging library is related to improper encoding or escaping of output data. Exploiting this vulnerability allows an attacker to influence the integrity of the protected information from a remote location...

Fedora 43 : log4cxx (2026-31a8569c4b)

The remote Fedora 43 host has a package installed that is affected by a vulnerability as referenced in the FEDORA-2026-31a8569c4b advisory. Update to log4cxx 1.7.0. Fixes CVE-2026-40023: XMLLayout did not escape characters forbidden by the XML 1.0 specification, which could cause conforming XML...

org.apache.logging.log4j/log4j-core: Apache Log4j Core: Invalid XML output causes denial of service in logging

A flaw was found in Apache Log4j Core. The XmlLayout component, responsible for formatting log messages into XML, does not properly remove or replace characters that are not allowed in XML 1.0. When log messages or diagnostic information contain these forbidden characters, the resulting XML outpu...

org.apache.logging.log4j/log4j-core: Apache Log4j Core: Invalid XML output causes denial of service in logging

A flaw was found in Apache Log4j Core. The XmlLayout component, responsible for formatting log messages into XML, does not properly remove or replace characters that are not allowed in XML 1.0. When log messages or diagnostic information contain these forbidden characters, the resulting XML outpu...

Updated log4cxx packages fix security vulnerability

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...

org.apache.logging.log4j/log4j-core: Apache Log4j Core: Invalid XML output causes denial of service in logging

A flaw was found in Apache Log4j Core. The XmlLayout component, responsible for formatting log messages into XML, does not properly remove or replace characters that are not allowed in XML 1.0. When log messages or diagnostic information contain these forbidden characters, the resulting XML outpu...

Apache Log4net: Silent Log Event Loss In XmlLayout And XmlLayoutSchemaLog4J Due To Unescaped XML 1.0 Forbidden Character

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...

SUSE 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...

SUSE 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...

Linux Distros Unpatched Vulnerability : CVE-2026-34480

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available. - 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...

Linux Distros Unpatched Vulnerability : CVE-2026-40021

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available. - Apache Log4net's XmlLayout https://logging.apache.org/log4net/manual/configuration/layouts.htmllayout- list and XmlLayoutSchemaLog4J...

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...

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-2026-21409

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-2026-21410

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...

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-2026-40021

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-2026-34480

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-2026-34479

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-2026-40021

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...