Vulnerability Analysis
Open WebUI: Stored XSS via unescaped KaTeX render-error fallback in rendered messages
CVE-2026-70492
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.
Cross-Site Scripting (XSS)
No Active Exploit Signals
CVSS Base Score
8.7
HIGH
Exploitability:2.3
Impact Score:5.8
Temporal Score:-
EPSS:0.26%
Threat Intelligence Signals
CISA KEV
No
KEV Date Added
—
Ransomware Use
—
KEV Due Date
—
VulnCheck In-the-Wild
No
Nuclei Template
No
EPSS Score
0.261%
EPSS Percentile
17.7th pct
GHSA ID
GitHub Severity
HIGH
SSVC Exploitation
Proof of Concept
SSVC Automatable
No
Vulnerability Class
Cross-Site Scripting (XSS)
Identity & Timeline
| Status | - |
| Assigning Authority | - |
| CVSS Version / Source | - |
| Reserved | - |
| Published | - |
| Patch Date (date_public) | - |
| Exploit DB Date | - |
| First GitHub PoC Date | - |
| Last Updated | - |
| Time to Patch (Days to fix) | - |
| Exploit Release Gap | - |
| PoC Release Gap | - |
| Exploit DB References | None identified |
Affected Products & Versions
| Vendor | Product | Affected Versions |
|---|---|---|
| No affected products specified. | ||
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