CVE-2026-100263: JetBrains Youtrack

Medium severity, CVSS 6.1. EPSS: 0.2% chance of exploitation in the next 30 days.

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

Affected products

• JetBrains Youtrack: before 2026.2.18991 (fixed in 2026.2.18991)

Published 2026-09-30. Last modified 2026-10-02.