This High severity com.thoughtworks.xstream:xstream Dependency vulnerability was introduced in versions 8.20.0, 9.0.0, 9.1.0, 9.2.0, 9.3.0, 9.4.0, 9.5.0, 9.6.0, and 9.7.0 of Jira Software Data Center and Server.

This com.thoughtworks.xstream:xstream Dependency 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:N/I:N/A:H allows an unauthenticated attacker to expose assets in your environment susceptible to exploitation which has no impact to confidentiality, no impact to integrity, high impact to availability, and requires no user interaction.

Atlassian recommends that Jira Software Data Center and Server customers upgrade to latest version, if you are unable to do so, upgrade your instance to one of the specified supported fixed versions:

See the release notes (https://www.atlassian.com/software/jira/download-archives). You can download the latest version of Jira Software Data Center and Server from the download center (https://www.atlassian.com/software/jira/download-archives).

The National Vulnerability Database provides the following description for this vulnerability: XStream serializes Java objects to XML and back again. Versions prior to 1.4.20 may allow a remote attacker to terminate the application with a stack overflow error, resulting in a denial of service only via manipulation the processed input stream. The attack uses the hash code implementation for collections and maps to force recursive hash calculation causing a stack overflow. This issue is patched in version 1.4.20 which handles the stack overflow and raises an InputManipulationException instead. A potential workaround for users who only use HashMap or HashSet and whose XML refers these only as default map or set, is to change the default implementation of java.util.Map and java.util per the code example in the referenced advisory. However, this implies that your application does not care about the implementation of the map and all elements are comparable.