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 products
openwebui: open webui
References5
- github.com/open-webui/open-webui/pull/26718 PatchVendor Advisory
- github.com/open-webui/open-webui/security/advisories/GHSA-pwxh-… ExploitPatchVendor Advisory
- github.com/open-webui/open-webui/security/advisories/GHSA-pwxh-… ExploitPatchVendor Advisory
- github.com/open-webui/open-webui/commit/bc600d3f085802c45aa8f38… Patch
- github.com/open-webui/open-webui/releases/tag/v0.11.0 Release Notes
Metrics
- CVSS 3.1
-
5.4
MEDIUM
Score source: NVD
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N - EPSS — exploit probability
- 0% percentile: 35 · as of 13 November 2026
- CWE
- CWE-79
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.