Atlassian JIRA: CVE-2026-34483: Improper Encoding org.apache.tomcat:tomcat-catalina Dependency in Jira Software Data Center

This High severity Improper Encoding vulnerability known as CVE-2026-34483 was introduced in version 11.3.0.
This Improper Encoding or Escaping of Output vulnerability, with a CVSS Score of 7.5 and a CVSS Vector of CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N allows an unauthenticated attacker to potentially disclose sensitive information via the Apache Tomcat JsonAccessLogValve, which has high impact to confidentiality, no impact to integrity, no impact to availability, and requires no user interaction.
Atlassian recommends that Jira Software Data Center and Server customers upgrade to the latest version. If you are unable to do so, upgrade your instance to one of the specified supported fixed versions:
* Jira Software Data Center and Server 11.3: Upgrade to a release greater than or equal to 11.3.5
* Jira Software Data Center and Server 10.3.20: Upgrade to a release greater than or equal to 10.3.20

See the release notes (https://confluence.atlassian.com/jirasoftware/jira-software-data-center-release-notes.html). You can download the latest version of Jira Software Data Center and Server from the Jira Data Center Download Archives | Atlassian.
The National Vulnerability Database provides the following description for this vulnerability:
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.