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CVE-2026-34483 High

Apache Tomcat: Incomplete escaping of JSON access logs

Improper Encoding or Escaping of Output vulnerability in the JsonAccessLogValve component of Apache Tomcat. This issue affects Apache Tomcat: from 11.0.0 through 11.0.20, from 10.1.0 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.

Exploit probability 0.5%
Published April 13, 2026
Required by Not available
Last source change April 13, 2026

02 / AFFECTED SOFTWARE

Affected packages

Unknown Unknown
Maven org.apache.tomcat.embed:tomcat-embed-core

165 explicit affected versions

Maven org.apache.tomcat:tomcat

165 explicit affected versions

Maven org.apache.tomcat:tomcat-catalina

165 explicit affected versions

Bitnami tomcat

03 / CONNECTIONS

Connected vulnerabilities

04 / EVIDENCE

Source records

Open Source Vulnerabilities CVE-2026-34483

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.

View original source
Open Source Vulnerabilities GHSA-rv64-5gf8-9qq8

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.

View original source
Open Source Vulnerabilities BIT-tomcat-2026-34483

Improper Encoding or Escaping of Output vulnerability in the JsonAccessLogValve component of Apache Tomcat. This issue affects Apache Tomcat: from 11.0.0 through 11.0.20, from 10.1.0 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.

View original source

05 / REFERENCES

Further evidence