CVE-2026-109290 Open WebUI 0.11.1 before 0.11.4 Stored XSS via DOCX Preview
Authenticated users can execute scripts via crafted DOCX uploads to steal admin session tokens and take over the instance.
- 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-2026-109290?
CVE-2026-109290 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 from 0.11.1 before 0.11.4 contains a stored cross-site scripting vulnerability in DocxPreview.svelte that allows authenticated users to execute script by uploading crafted DOCX attachments. Attackers can embed an OOXML altChunk HTML part or script-scheme hyperlink to steal a previewing administrator's session token from local storage and take over the instance.
Which versions are affected by CVE-2026-109290?
How do I fix CVE-2026-109290?
No fix has been published for CVE-2026-109290 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-2026-109290 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-109290 exists.
Sources
Also known as GHSA-39h3-jjqw-8pch, GHSA-f9xp-mfmq-x6cg.