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CVE-2026-34479

Опубликовано: 10 апр. 2026
Источник: redhat
CVSS3: 5.3

Описание

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 processing systems to drop or fail to index affected records. Two groups of users are affected:

  • Those using Log4j1XmlLayout directly in a Log4j Core 2 configuration file.
  • Those using the Log4j 1 configuration compatibility layer with org.apache.log4j.xml.XMLLayout specified as the layout class. Users are advised to upgrade to Apache Log4j 1-to-Log4j 2 bridge version 2.25.4, which corrects this issue. Note: The Apache Log4j 1-to-Log4j 2 bridge is deprecated and will not be present in Log4j 3. Users are encouraged to consult the Log4j 1 to Log4j 2 migration guide https://logging.apache.org/log4j/2.x/migrate-from-log4j1.html , and specifically the section on eliminating reliance on the bridge.

    A flaw was found in the Apache Log4j 1-to-Log4j 2 bridge. The Log4j1XmlLayout component fails to properly escape characters forbidden by the XML 1.0 standard. This improper handling of characters results in malformed XML output, which can cause downstream log processing systems to drop or fail to index affected records. The primary consequence is a denial of service for log analysis, potentially hindering security monitoring and incident response.

Меры по смягчению последствий

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.

Затронутые пакеты

ПлатформаПакетСостояниеРекомендацияРелиз
Red Hat Data Grid 8log4j-1.2-apiFix deferred
Red Hat Enterprise Linux 8log4j:2/log4jFix deferred
Red Hat Enterprise Linux 9log4jOut of support scope
Red Hat Fuse 7log4j-1.2-apiFix deferred
Red Hat JBoss Enterprise Application Platform 7log4j-1.2-apiFix deferred
Red Hat JBoss Enterprise Application Platform 8log4j-1.2-apiFix deferred
Red Hat JBoss Enterprise Application Platform Expansion Packlog4j-1.2-apiFix deferred
Red Hat Offline Knowledge Portalredhat-user-workloads/rhokp-core-encryptedFix deferred
Red Hat OpenShift AI (RHOAI)rhoai/odh-modelmesh-rhel8Fix deferred
Red Hat OpenShift AI (RHOAI)rhoai/odh-modelmesh-rhel9Fix deferred

Показывать по

Дополнительная информация

Статус:

Moderate
Дефект:
CWE-91
https://bugzilla.redhat.com/show_bug.cgi?id=2457313org.apache.logging.log4j/log4j-1.2-api: Apache Log4j 1-to-Log4j 2 bridge: Log processing denial of service due to improper XML escaping

5.3 Medium

CVSS3

Связанные уязвимости

CVSS3: 7.5
ubuntu
4 месяца назад

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 processing systems to drop or fail to index affected records. Two groups of users are affected: * Those using Log4j1XmlLayout directly in a Log4j Core 2 configuration file. * Those using the Log4j 1 configuration compatibility layer with org.apache.log4j.xml.XMLLayout specified as the layout class. Users are advised to upgrade to Apache Log4j 1-to-Log4j 2 bridge version 2.25.4, which corrects this issue. Note: The Apache Log4j 1-to-Log4j 2 bridge is deprecated and will not be present in Log4j 3. Users are encouraged to consult the Log4j 1 to Log4j 2 migration guide https://logging.apache.org/log4j/2.x/migrate-from-log4j1.html , and specifically the section on eliminating reliance on the bridge.

CVSS3: 7.5
nvd
4 месяца назад

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 processing systems to drop or fail to index affected records. Two groups of users are affected: * Those using Log4j1XmlLayout directly in a Log4j Core 2 configuration file. * Those using the Log4j 1 configuration compatibility layer with org.apache.log4j.xml.XMLLayout specified as the layout class. Users are advised to upgrade to Apache Log4j 1-to-Log4j 2 bridge version 2.25.4, which corrects this issue. Note: The Apache Log4j 1-to-Log4j 2 bridge is deprecated and will not be present in Log4j 3. Users are encouraged to consult the Log4j 1 to Log4j 2 migration guide https://logging.apache.org/log4j/2.x/migrate-from-log4j1.html , and specifically the section on eliminating reliance on the br

msrc
4 месяца назад

Apache Log4j 1 to Log4j 2 bridge: Silent log event loss in Log4j1XmlLayout due to unescaped XML 1.0 forbidden characters

CVSS3: 7.5
debian
4 месяца назад

The Log4j1XmlLayout from the Apache Log4j 1-to-Log4j 2 bridge fails to ...

github
4 месяца назад

Apache Log4j 1 to Log4j 2 bridge: silent log event loss in Log4j1XmlLayout due to unescaped XML 1.0 forbidden characters

5.3 Medium

CVSS3