CVE-2026-34483
Received Received - Intake
Improper Output Encoding Vulnerability in Apache Tomcat JsonAccessLogValve

Publication date: 2026-04-09

Last updated on: 2026-04-14

Assigner: Apache Software Foundation

Description
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.
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Meta Information
Published
2026-04-09
Last Modified
2026-04-14
Generated
2026-06-16
AI Q&A
2026-04-09
EPSS Evaluated
2026-06-15
NVD
CVE-2026-34483
EUVD
EUVD-2026-21053
Affected Vendors & Products
Showing 3 associated CPEs
Vendor Product Version / Range
apache tomcat From 10.1.0 (inc) to 10.1.54 (exc)
apache tomcat From 11.0.0 (inc) to 11.0.21 (exc)
apache tomcat From 9.0.40 (inc) to 9.0.117 (exc)
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-116 The product prepares a structured message for communication with another component, but encoding or escaping of the data is either missing or done incorrectly. As a result, the intended structure of the message is not preserved.
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Executive Summary

This vulnerability is an Improper Encoding or Escaping of Output issue found in the JsonAccessLogValve component of Apache Tomcat. It affects multiple versions of Apache Tomcat, specifically from 11.0.0-M1 through 11.0.20, 10.1.0-M1 through 10.1.53, and 9.0.40 through 9.0.116.

Improper encoding or escaping means that the component may not correctly handle special characters in output, which can lead to security issues such as injection attacks or data corruption.

Impact Analysis

The impact of this vulnerability could include potential security risks arising from improper handling of output data in the logging component. This might allow attackers to inject malicious content or cause incorrect log entries, which can hinder security monitoring or lead to further exploitation.

Users of affected Apache Tomcat versions are advised to upgrade to fixed versions (11.0.21, 10.1.54, or 9.0.117) to mitigate these risks.

Mitigation Strategies

Users are recommended to upgrade Apache Tomcat to version 11.0.21, 10.1.54, or 9.0.117, which fix the Improper Encoding or Escaping of Output vulnerability in the JsonAccessLogValve component.

Compliance Impact

The provided information does not specify how the improper encoding or escaping vulnerability in Apache Tomcat's JsonAccessLogValve component directly affects compliance with common standards and regulations such as GDPR or HIPAA.

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