CVE-2026-109288 Open WebUI before 0.11.4 Stored XSS via javascript: URLs in Markdown Links
Authenticated users can inject JavaScript via Markdown links to steal JWT tokens from victims, including admins, in Open WebUI.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-109288?
CVE-2026-109288 is a high-severity cross-site scripting vulnerability in open-webui, published on 12 Oct 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official description
Open WebUI before 0.11.4 contains a stored cross-site scripting vulnerability in MarkdownInlineTokens.svelte, which renders markdown link URLs into anchor hrefs without validating their scheme. Authenticated users can embed javascript: links in shared chats that, when clicked by a victim, steal the victim's JWT from local storage, including admins' tokens.
Weakness: CWE-79
Which versions are affected by CVE-2026-109288?
How do I fix CVE-2026-109288?
No fix has been published for CVE-2026-109288 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-2026-109288 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-109288 exists.
Sources
Also known as GHSA-fhg2-q543-9wpq, GHSA-wf9m-46cp-c6h6.