CVE-2026-86491 Cross-site scripting in YouTrack
Attackers can execute arbitrary scripts in victim browsers via malicious icon uploads in JetBrains YouTrack, potentially leading to session hijacking.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-86491?
CVE-2026-86491 is a low-severity cross-site scripting vulnerability in JetBrains YouTrack, published on 7 Sep 2026. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.
Official description
In JetBrains YouTrack before 2026.2.18634 stored XSS was possible via project and organization icon uploads
Weakness: CWE-79
Which versions are affected by CVE-2026-86491?
How do I fix CVE-2026-86491?
No fix has been published for CVE-2026-86491 yet. Limit exposure of the affected software until one is available.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-86491 being exploited?
There is no known exploitation of CVE-2026-86491 in the wild and no public exploit code.
Sources
Also known as GHSA-m4mg-c2jx-4939.