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CVE-2026-34483

HIGH

Apache Tomcat has an Improper Encoding or Escaping of Output vulnerability in the JsonAccessLogValve

Published April 9, 2026Updated April 16, 2026Source: osv

Summary

Improper Encoding or Escaping of Output vulnerability in the JsonAccessLogValve component of Apache Tomcat. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.20, from 10.1.0-M1 through 10.1.53, from 9.0.40 through 9.0.116. Users are recommended to upgrade to version 11.0.21, 10.1.54 or 9.0.117 , which fix the issue.

Remediation

Upgrade to the fixed version using your package manager.

Maven
Update org.apache.tomcat:tomcat to 9.0.116 or later
<!-- Update pom.xml dependency version to 9.0.116 for org.apache.tomcat:tomcat -->
Maven
Update org.apache.tomcat:tomcat to 11.0.21 or later
<!-- Update pom.xml dependency version to 11.0.21 for org.apache.tomcat:tomcat -->
Maven
Update org.apache.tomcat:tomcat-catalina to 9.0.116 or later
<!-- Update pom.xml dependency version to 9.0.116 for org.apache.tomcat:tomcat-catalina -->
Maven
Update org.apache.tomcat:tomcat-catalina to 11.0.21 or later
<!-- Update pom.xml dependency version to 11.0.21 for org.apache.tomcat:tomcat-catalina -->
Maven
Update org.apache.tomcat.embed:tomcat-embed-core to 11.0.21 or later
<!-- Update pom.xml dependency version to 11.0.21 for org.apache.tomcat.embed:tomcat-embed-core -->
Maven
Update org.apache.tomcat:tomcat to 10.1.54 or later
<!-- Update pom.xml dependency version to 10.1.54 for org.apache.tomcat:tomcat -->
Maven
Update org.apache.tomcat:tomcat-catalina to 10.1.54 or later
<!-- Update pom.xml dependency version to 10.1.54 for org.apache.tomcat:tomcat-catalina -->
Maven
Update org.apache.tomcat.embed:tomcat-embed-core to 10.1.54 or later
<!-- Update pom.xml dependency version to 10.1.54 for org.apache.tomcat.embed:tomcat-embed-core -->
Maven
Update org.apache.tomcat.embed:tomcat-embed-core to 9.0.116 or later
<!-- Update pom.xml dependency version to 9.0.116 for org.apache.tomcat.embed:tomcat-embed-core -->

After upgrading, run your dependency scanner again to confirm the vulnerability is resolved.

Affected Packages (9)

PackageEcosystemAffectedFixed In
org.apache.tomcat:tomcat
maven
9.0.100, 9.0.102, 9.0.104, 9.0.105 (+60 more)9.0.116
org.apache.tomcat:tomcat
maven
11.0.0, 11.0.0-M1, 11.0.0-M10, 11.0.0-M11 (+37 more)11.0.21
org.apache.tomcat:tomcat-catalina
maven
9.0.100, 9.0.102, 9.0.104, 9.0.105 (+60 more)9.0.116
org.apache.tomcat:tomcat-catalina
maven
11.0.0, 11.0.0-M1, 11.0.0-M10, 11.0.0-M11 (+37 more)11.0.21
org.apache.tomcat.embed:tomcat-embed-core
maven
11.0.0, 11.0.0-M1, 11.0.0-M10, 11.0.0-M11 (+37 more)11.0.21
org.apache.tomcat:tomcat
maven
10.1.0, 10.1.0-M1, 10.1.0-M10, 10.1.0-M11 (+56 more)10.1.54
org.apache.tomcat:tomcat-catalina
maven
10.1.0, 10.1.0-M1, 10.1.0-M10, 10.1.0-M11 (+56 more)10.1.54
org.apache.tomcat.embed:tomcat-embed-core
maven
10.1.0, 10.1.0-M1, 10.1.0-M10, 10.1.0-M11 (+56 more)10.1.54
org.apache.tomcat.embed:tomcat-embed-core
maven
9.0.100, 9.0.102, 9.0.104, 9.0.105 (+60 more)9.0.116

Vulnerability Classification

Common Weakness Enumeration (CWE) identifiers for this vulnerability type.

  • CWE-116
    Improper Encoding or EscapingMITRE

CVSS Score Breakdown

What the CVSS (Common Vulnerability Scoring System) 7.5 score means for each attack dimension.

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

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

References

Frequently Asked Questions

What is CVE-2026-34483?
Apache Tomcat has an Improper Encoding or Escaping of Output vulnerability in the JsonAccessLogValve This vulnerability has been assigned a severity rating of HIGH (CVSS score: 7.5/10).
How do I check if my project is affected by CVE-2026-34483?
CVE-2026-34483 affects org.apache.tomcat:tomcat, org.apache.tomcat:tomcat-catalina and org.apache.tomcat.embed:tomcat-embed-core. Use GeekWala's free vulnerability scanner to check your dependencies against CVE-2026-34483 and 200,000+ other known vulnerabilities.

Severity & Exploitability

CVSS Score
7.5

High exploitability or significant impact. Prioritize remediation within days.

Also Known As

GHSA-rv64-5gf8-9qq8
BIT-tomcat-2026-34483

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