The AssociateFieldToScreens page in Atlassian Jira Server and Data Center before version 8.18.0 allows remote attackers to inject arbitrary HTML or JavaScript via a Cross-Site Scripting (XSS) vulnerability via the name of a custom field.
Conclusion & alert: CVE-2021-39117 is rated Low Risk (35.2/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.61%).Mandatory action: Monitor for updates and reassess as exploit intelligence or EPSS changes.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
Exploit prediction scoring system (EPSS) score for CVE-2021-39117
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).