Vulnerability · Published Aug 4, 2026 · Assigned by GitHub_M
CVE-2026-70492Open WebUI: Stored XSS via unescaped KaTeX render-error fallback in rendered messages
High 8.7
In plain English
A high-severity cross-site scripting in open-webui from open-webui. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 35% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
Open WebUI is an extensible, feature-rich, and user-friendly self-hosted AI platform. From 0.10.0 until 0.11.0, src/lib/components/chat/Messages/Markdown/KatexRenderer.svelte could store and render a chat message whose math block makes KaTeX fail with a stack overflow instead of a parse error. The catch branch fell back to inserting the original math source into the page as HTML through {@html} rather than as text, so script in the message runs in the browser of whoever views it, including shared chats and channels. The viewer's session token in localStorage can be stolen, and an administrator viewer can have their account taken over. This issue is fixed in 0.11.0.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| PyPI | open-webui | 0.11.0 | GHSA-pwxh-7358-jq2x |
| PyPI | open-webui | 0.11.0 | PYSEC-2026-3650 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| open-webui | open-webui | >= 0.10.0, < 0.11.0 |
Weakness: CWE-79 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N
References
- https://github.com/open-webui/open-webui/security/advisories/GHSA-pwxh-7358-jq2x x_refsource_CONFIRM
- https://github.com/open-webui/open-webui/pull/26718 x_refsource_MISC
- https://github.com/open-webui/open-webui/commit/bc600d3f085802c45aa8f38c30e6e8c986bde6cc x_refsource_MISC
- https://github.com/open-webui/open-webui/releases/tag/v0.11.0 x_refsource_MISC