CVE-2026-70492

Open WebUI: Stored XSS via unescaped KaTeX render-error fallback in rendered messages

Published Aug 4, 2026 CVSS 3.1 · 8.7 High EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-pwxh-7358-jq2x Open WebUI: Stored XSS via unescaped KaTeX render-error fallback in rendered messages
History
Type Values Removed Values Added
First Time appeared Openwebui
Openwebui open Webui
CPEs cpe:2.3:a:openwebui:open_webui:*:*:*:*:*:*:*:*
Vendors & Products Openwebui
Openwebui open Webui
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Open-webui
Open-webui open-webui
Vendors & Products Open-webui
Open-webui open-webui
Type Values Removed Values Added
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.
Title Open WebUI: Stored XSS via unescaped KaTeX render-error fallback in rendered messages
Weaknesses CWE-79
References
Metrics cvssV3_1

{'score': 8.7, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Aug 5, 2026, 2:41 PM
Reserved
Aug 4, 2026, 3:24 PM
Status
Analyzed
Published
Aug 4, 2026, 9:16 PM
Modified
Sep 18, 2026, 2:47 PM