Improper Restriction of Rendered UI Layers or Frames in YouTrack - CVE-2026-59791
Published: August 17, 2026
Vulnerability identifier: #VU143842
CSH Severity: Low
CVSS v4: 5.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-59791
CWE-ID: CWE-1021
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to inject malicious css.
The vulnerability exists due to improper restriction of rendered ui layers or frames in mermaid diagram rendering when rendering user-supplied mermaid diagrams. A remote user can create a specially crafted diagram to inject malicious css.
Affected software
YouTrack
How to mitigate CVE-2026-59791
Install security update from vendor's website.
YouTrack - update to 2026.2.17012