CVE-2026-34479

HighCVSS 7.5/10Last modified Jun 17, 2026

Description

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.

Metrics

CVSS 3.1 7.5/10CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Weakness enumeration

CWE-116

Affected software

No affected versions have been published.

Timeline

Published: Apr 10, 2026
Last modified: Jun 17, 2026
NVD status: Analyzed

Related CVEs from 2026

CVE-2026-344807.5Apache Log4j Core's XmlLayout https://logging.apache.org/log4j/2.x/manual/layouts.html#XmlLayout , in versions up to and including 2.25.3, CVE-2026-344817.5Apache Log4j's JsonTemplateLayout https://logging.apache.org/log4j/2.x/manual/json-template-layout.html , in versions up to and including 2 CVE-2026-344837.5Improper Encoding or Escaping of Output vulnerability in the JsonAccessLogValve component of Apache Tomcat. This issue affects Apache Tomca CVE-2026-34484Nokia 1830 Global Express GX is vulnerable to a local privilege escalation vulnerability which exists in the administrative shell interface.CVE-2026-34485Nokia 1830 Global Express (GX) is vulnerable to a CLI ACL Bypass vulnerability where a low-privileged authenticated attacker can bypass the CVE-2026-344867.5Missing Encryption of Sensitive Data vulnerability in Apache Tomcat due to the fix for CVE-2026-29146 allowing the bypass of the EncryptInte CVE-2026-344877.5Insertion of Sensitive Information into Log File vulnerability in the cloud membership for clustering component of Apache Tomcat exposed the CVE-2026-344887.0IP Setting Software contains an issue with the DLL search path, which may lead to insecurely loading Dynamic Link Libraries. As a result, ar CVE-2026-34493.3Versions of the package @tootallnate/once before 3.0.1 are vulnerable to Incorrect Control Flow Scoping in promise resolving when AbortSigna CVE-2026-344905.5Cleartext storage of sensitive information vulnerability in Johnson Controls XAAP Application on Android allows an attacker on a jailbroken CVE-2026-344916.1Improper neutralization of input during web page generation ('cross-site scripting') vulnerability in Johnson Controls Metasys 14 and Johnso CVE-2026-344927.0External control of file name or path vulnerability in Johnson Controls Airwall allows : File Manipulation. This issue affects Airwall: bef