Reflected XSS via /rest/collectors/1.0/template/custom - CVE-2021-43942

Affected versions of Atlassian Jira Server and Data Center allow remote attackers to inject arbitrary HTML or JavaScript via a Reflected Cross-Site Scripting (XSS) vulnerability in the /rest/collectors/1.0/template/custom endpoint. To exploit this issue, the attacker must trick a user into visiting a malicious website.

The affected versions are before version 8.13.15, and from version 8.14.0 before 8.20.3.

Affected versions:

• version < 8.13.15
• 8.14.0 ≤ version < 8.20.3

Fixed versions:

• 8.13.15
• 8.20.3
• 8.21.0