Improper Encoding or Escaping of Output in Apache Tomcat - CVE-2026-34483

Vulnerability identifier: #VU125747

CSH Severity: Medium

CVSS v4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-34483

CWE-ID: CWE-116

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to inject arbitrary JSON into the JSON access log.

The vulnerability exists due to incomplete escaping in the JSON access log when handling requests with non-default Connector attributes relaxedPathChars and/or relaxedQueryChars. A remote attacker can send a specially crafted request to inject arbitrary JSON into the JSON access log.

Only configurations using non-default values for relaxedPathChars and/or relaxedQueryChars are affected.

Apache Tomcat
Debian Linux
SUSE Linux Enterprise Server 15 SP5
SUSE Linux Enterprise Server 15 SP6
SUSE Linux Enterprise Server 15 SP4
SUSE Linux Enterprise Server 12 SP5 LTSS Extended
SUSE Linux Enterprise Server 12 SP5
SUSE Linux Enterprise High Performance Computing LTSS 15
SUSE Linux Enterprise High Performance Computing 15
SUSE Linux Enterprise High Performance Computing ESPOS 15
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Linux Enterprise Server for SAP Applications 12
SUSE Linux Enterprise Server 12
SUSE Linux Enterprise High Performance Computing 12
Web and Scripting Module
openSUSE Leap
openEuler
Anolis OS
Storage Defender Copy Data Management
Integration Bus for z/OS
CICS Transaction Gateway Desktop Edition
CICS Transaction Gateway for Multiplatforms
ApplinX
MongoDB Enterprise Advanced with IBM
IBM Watson Discovery for IBM Cloud Pak for Data
Confluence Data Center
Bamboo Data Center
Jira Software Data Center
Jira Service Management Data Center
Datastax Enterprise with IBM
IBM Qradar SIEM
tomcat-help
tomcat-webapps
tomcat-servlet-4.0-api
tomcat-lib
tomcat-el-3.0-api
tomcat
tomcat-jsvc
tomcat-admin-webapps
tomcat-doc
tomcat-jsp-2.3-api
tomcat-docs-webapp
tomcat-el-3_0-api
tomcat-jsp-2_3-api
tomcat-servlet-4_0-api
tomcat-javadoc
tomcat10-admin-webapps
tomcat10-el-5_0-api
tomcat10-lib
tomcat10-servlet-6_0-api
tomcat10-webapps
tomcat10
tomcat10-jsp-3_1-api
tomcat10 (Debian package)
tomcat11-lib
tomcat11-embed
tomcat11-doc
tomcat11-jsp-4_0-api
tomcat11-jsvc
tomcat11-servlet-6_1-api
tomcat11-el-6_0-api
tomcat11-admin-webapps
tomcat11-docs-webapp
tomcat11
tomcat11-webapps
tomcat11 (Debian package)

Install security update from vendor's website.

Apache Tomcat - addressed in versions 9.0.117, 10.1.54, 11.0.21
Storage Defender Copy Data Management - update to 2.3.0.1
IBM Watson Discovery for IBM Cloud Pak for Data - update to 5.3.2
IBM Qradar SIEM - update to 7.5.0 Update Pack 15 IF05
Confluence Data Center - addressed in versions 9.2.20, 10.2.11
Bamboo Data Center - addressed in versions 9.6.25, 10.2.18, 12.1.7
Jira Software Data Center - addressed in versions 10.3.20, 11.3.5
Jira Service Management Data Center - addressed in versions 10.3.20, 11.3.5
MongoDB Enterprise Advanced with IBM - update to 1.16.0
Datastax Enterprise with IBM - update to 6.9.22
tomcat-help - update to 9.0.117-1
tomcat-webapps - update to 9.0.117-1
tomcat-servlet-4.0-api - update to 9.0.117-1
tomcat-lib - update to 9.0.117-1
tomcat-el-3.0-api - update to 9.0.117-1
tomcat - update to 9.0.117-1
tomcat-jsvc - update to 9.0.117-1
tomcat - update to 9.0.117-1
tomcat-admin-webapps - update to 9.0.117-1
tomcat-doc - update to 9.0.117-1
tomcat-jsp-2.3-api - update to 9.0.117-1
tomcat-docs-webapp - update to 9.0.117-1
tomcat-el-3_0-api - addressed in versions 9.0.117-3.163.2, 9.0.117-150200.105.1
tomcat-webapps - addressed in versions 9.0.117-3.163.2, 9.0.117-150200.105.1
tomcat-admin-webapps - addressed in versions 9.0.117-3.163.2, 9.0.117-150200.105.1
tomcat-jsp-2_3-api - addressed in versions 9.0.117-3.163.2, 9.0.117-150200.105.1
tomcat-servlet-4_0-api - addressed in versions 9.0.117-3.163.2, 9.0.117-150200.105.1
tomcat - addressed in versions 9.0.117-3.163.2, 9.0.117-150200.105.1
tomcat-lib - addressed in versions 9.0.117-3.163.2, 9.0.117-150200.105.1
tomcat-docs-webapp - update to 9.0.117-3.163.2
tomcat-javadoc - update to 9.0.117-3.163.2
tomcat10-admin-webapps - update to 10.1.54-150200.5.64.1
tomcat10-el-5_0-api - update to 10.1.54-150200.5.64.1
tomcat10-lib - update to 10.1.54-150200.5.64.1
tomcat10-servlet-6_0-api - update to 10.1.54-150200.5.64.1
tomcat10-webapps - update to 10.1.54-150200.5.64.1
tomcat10 - update to 10.1.54-150200.5.64.1
tomcat10-jsp-3_1-api - update to 10.1.54-150200.5.64.1
tomcat10 (Debian package) - addressed in versions 10.1.55-1~deb12u1, 10.1.55-1~deb13u1
tomcat11-lib - update to 11.0.21-150600.13.18.1
tomcat11-embed - update to 11.0.21-150600.13.18.1
tomcat11-doc - update to 11.0.21-150600.13.18.1
tomcat11-jsp-4_0-api - update to 11.0.21-150600.13.18.1
tomcat11-jsvc - update to 11.0.21-150600.13.18.1
tomcat11-servlet-6_1-api - update to 11.0.21-150600.13.18.1
tomcat11-el-6_0-api - update to 11.0.21-150600.13.18.1
tomcat11-admin-webapps - update to 11.0.21-150600.13.18.1
tomcat11-docs-webapp - update to 11.0.21-150600.13.18.1
tomcat11 - update to 11.0.21-150600.13.18.1
tomcat11-webapps - update to 11.0.21-150600.13.18.1
tomcat11 (Debian package) - update to 11.0.22-1~deb13u1

• https://tomcat.apache.org/security-11.html#Fixed_in_Apache_Tomcat_11.0.21
• https://tomcat.apache.org/security-10.html#Fixed_in_Apache_Tomcat_10.1.54
• https://tomcat.apache.org/security-9.html#Fixed_in_Apache_Tomcat_9.0.117
• https://lists.apache.org/thread/xyv1hpj484orlzkxr63qgom9rddhwo5z

• Multiple vulnerabilities in Apache Tomcat (April 2026 release)
• openEuler update for tomcat
• Anolis OS update for tomcat
• SUSE update for tomcat11
• SUSE update for tomcat
• SUSE update for tomcat10
• SUSE update for tomcat
• Multiple vulnerabilities in IBM Storage Defender Copy Data Management
• Multiple vulnerabilities in IBM Integration Bus for z/OS
• Multiple vulnerabilities in IBM DataStax Enterprise
• Multiple vulnerabilities in Bamboo Data Center
• Multiple vulnerabilities in Confluence Data Center
• Multiple vulnerabilities in Jira Service Management Data Center
• Multiple vulnerabilities in Jira Software Data Center
• Debian update for tomcat11
• Debian update for tomcat10
• Multiple vulnerabilities in MongoDB Enterprise Advanced with IBM
• Multiple vulnerabilities in IBM ApplinX
• Multiple vulnerabilities in IBM Watson Discovery Cartridge
• Multiple vulnerabilities in IBM CICS Transaction Gateway for Multiplatforms
• Multiple vulnerabilities in CICS Transaction Gateway Desktop Edition
• Multiple vulnerabilities in IBM QRadar SIEM