CVE-2026-100263 Cross-site scripting in YouTrack
Attackers can inject malicious HTML via the User-Agent header in JetBrains YouTrack, potentially leading to script execution or account takeover.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-100263?
CVE-2026-100263 is a medium-severity cross-site scripting vulnerability in Jetbrains Youtrack, published on 30 Sep 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
In JetBrains YouTrack before 2026.2.18991 stored HTML injection via the User-Agent header was possible
Weakness: CWE-79
Which versions are affected by CVE-2026-100263?
It affects 1 product.
Products include Jetbrains Youtrack.
How do I fix CVE-2026-100263?
No fix has been published for CVE-2026-100263 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-2026-100263 being exploited?
There is no known exploitation of CVE-2026-100263 in the wild and no public exploit code.
Other vulnerabilities in Jetbrains Youtrack
Sources
Also known as GHSA-wpxv-jj6h-wjr5.