All vulnerabilities
CVE-2026-100263

In JetBrains YouTrack before 2026.2.18991 stored HTML injection via the User-Agent header was possible

JetBrains YouTrack
Open in ThreatlineRecord JSON
CVSS
4.7Medium
ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.19%Chance of exploitation activity in the next 30 days, higher than 8% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed in2026.2.18991Fixed versionCVE List
Published30 Sep 2026Updated 30 Sep 2026CVE List

What fixes it

A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.

Affected versions 1

  • YouTrackaffected: all versions before 2026.2.18991CVE List

References 1