CVE-2026-34483
Improper Output Encoding Vulnerability in Apache Tomcat JsonAccessLogValve
Publication date: 2026-04-09
Last updated on: 2026-04-14
Assigner: Apache Software Foundation
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| 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 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. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
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.
How can this vulnerability impact me? :
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.
What immediate steps should I take to mitigate this vulnerability?
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.
How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:
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.