CVE-2026-70492
📛 CVE Title
Open WebUI: Stored XSS via unescaped KaTeX render-error fallback in rendered messages
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.
Overview
- State
- PUBLISHED
- Assigner (CNA)
- GitHub_M
- CVSS severity
- HIGH
- CVSS score
- 8.7 / 10
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N- Effective score
- 8.7 / 10 HIGH source: CNA overview
- CWE(s)
-
CWE-79 - Reserved
- 2026-08-04
- Published
- 2026-08-04 20:53 UTC
- Last updated
- 2026-08-04 20:53 UTC
- Source
- https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/70xxx/CVE-2026-70492.json
- Linked Threat
- CVE-2026-70492 — Open WebUI: Stored XSS via unescaped KaTeX render-error fallback in rendered messages
Affected products (1)
| Vendor | Product | Versions | Platforms |
|---|---|---|---|
| open-webui | open-webui |
>= 0.10.0, < 0.11.0 (affected)
|
— |
Vendor references (4)
References embedded in the original CVE record by the assigning CNA.
- https://github.com/open-webui/open-webui/security/advisories/GHSA-pwxh-7358-jq2x x_refsource_CONFIRM
- https://github.com/open-webui/open-webui/pull/26718 x_refsource_MISC
- https://github.com/open-webui/open-webui/commit/bc600d3f085802c45aa8f38c30e6e8c986bde6cc x_refsource_MISC
- https://github.com/open-webui/open-webui/releases/tag/v0.11.0 x_refsource_MISC
Web references (0)
DuckDuckGo results ranked by threat-intel / vendor advisory domains. Generated by the 🔎 Find references (web) button above — same flow as the Remediations search.
No web references attached yet.
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Raw JSON
The full cvelistV5 record. Download as CVE-2026-70492.json.
{
"containers": {
"cna": {
"affected": [
{
"product": "open-webui",
"vendor": "open-webui",
"versions": [
{
"status": "affected",
"version": ">= 0.10.0, < 0.11.0"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "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."
}
],
"metrics": [
{
"cvssV3_1": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "NONE",
"baseScore": 8.7,
"baseSeverity": "HIGH",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "LOW",
"scope": "CHANGED",
"userInteraction": "REQUIRED",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N",
"version": "3.1"
}
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-79",
"description": "CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-04T20:53:36.141Z",
"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
"shortName": "GitHub_M"
},
"references": [
{
"name": "https://github.com/open-webui/open-webui/security/advisories/GHSA-pwxh-7358-jq2x",
"tags": [
"x_refsource_CONFIRM"
],
"url": "https://github.com/open-webui/open-webui/security/advisories/GHSA-pwxh-7358-jq2x"
},
{
"name": "https://github.com/open-webui/open-webui/pull/26718",
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/open-webui/open-webui/pull/26718"
},
{
"name": "https://github.com/open-webui/open-webui/commit/bc600d3f085802c45aa8f38c30e6e8c986bde6cc",
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/open-webui/open-webui/commit/bc600d3f085802c45aa8f38c30e6e8c986bde6cc"
},
{
"name": "https://github.com/open-webui/open-webui/releases/tag/v0.11.0",
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/open-webui/open-webui/releases/tag/v0.11.0"
}
],
"source": {
"advisory": "GHSA-pwxh-7358-jq2x",
"discovery": "UNKNOWN"
},
"title": "Open WebUI: Stored XSS via unescaped KaTeX render-error fallback in rendered messages"
}
},
"cveMetadata": {
"assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
"assignerShortName": "GitHub_M",
"cveId": "CVE-2026-70492",
"datePublished": "2026-08-04T20:53:36.141Z",
"dateReserved": "2026-08-04T15:24:41.340Z",
"dateUpdated": "2026-08-04T20:53:36.141Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}