CVE-2026-70492 Details
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.
A stored cross-site scripting vulnerability has been identified in Open WebUI versions 0.10.0 prior to 0.11.0. The issue arises in the KaTeX renderer component, where improperly handled math blocks can cause a stack overflow. Instead of generating a parse error, the renderer defaults to inserting the original math source as HTML, which can execute scripts in the browsers of users viewing the message. This vulnerability is present in all message rendering surfaces, including shared chats and channels. The flaw allows for the theft of the viewer's session token, potentially leading to account takeover, especially if the viewer is an administrator.
Users can upgrade to Open WebUI version 0.11.0, which addresses this vulnerability by properly escaping the KaTeX error fallback before it reaches the DOM. No additional configuration changes are necessary.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Aug 5, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/open-webui/open-webui/security/advisories/GHSA-pwxh-7358-jq2x | CISA-ADP | ExploitPatchVendor Advisory |
| https://github.com/open-webui/open-webui/commit/bc600d3f085802c45aa8f38c30e6e8c986bde6cc | [email protected] | Patch |
| https://github.com/open-webui/open-webui/pull/26718 | [email protected] | PatchVendor Advisory |
| https://github.com/open-webui/open-webui/releases/tag/v0.11.0 | [email protected] | Release Notes |
| https://github.com/open-webui/open-webui/security/advisories/GHSA-pwxh-7358-jq2x | [email protected] | ExploitPatchVendor Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-79 | Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| openwebui open webui | >= 0.10.0, < 0.11.0 |
CPE
Remediation
| |
Change History
3 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Sep 18, 2026 | Initial Analysis | [email protected] |
| Aug 5, 2026 | CVE Modified | CISA-ADP |
| Aug 4, 2026 | New CVE Received | [email protected] |