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

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-70492
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-04 21:16:38 UTC
Updated2026-09-18 14:47:07 UTC
DescriptionOpen 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.

Risk And Classification

Primary CVSS: v3.1 5.4 MEDIUM from [email protected]

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

EPSS: 0.002660000 probability, percentile 0.187870000 (date 2026-09-20)

Problem Types: CWE-79 | CWE-79 CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

VersionSourceTypeScoreSeverityVector
3.1[email protected]Primary5.4MEDIUMCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
3.1[email protected]Secondary8.7HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N
3.1CNADECLARED8.7HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Openwebui Open Webui All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Open-webui Open-webui affected >= 0.10.0, < 0.11.0 Not specified

References

ReferenceSourceLinkTags
github.com/open-webui/open-webui/security/advisories/GHSA-pwxh-7358-jq2x 134c704f-9b21-4f2e-91b3-4a467353bcc0 github.com Exploit, Patch, Vendor Advisory
github.com/open-webui/open-webui/commit/bc600d3f085802c45aa8f38c30e6e8c9... [email protected] github.com Patch
github.com/open-webui/open-webui/pull/26718 [email protected] github.com Patch, Vendor Advisory
github.com/open-webui/open-webui/releases/tag/v0.11.0 [email protected] github.com Release Notes
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

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