Cross-Site Scripting (XSS) in open-webui (CVE-2026-70492)
Summary
Cross-site scripting in open-webui (CVE-2026-70492). Confidential information can be exposed externally. Exploitable via catch. Mitigation: upgrade to 0.11.0 or later.
Original description
The description as published by the source.
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.
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-70492 has been found in open-webui.
Attackers can target a specific entry point like catch over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 8.7/10.
What to do: upgrade open-webui to 0.11.0 or later.
If unsure, ask your IT team or search "open-webui CVE-2026-70492" on the vendor's site.
CVE-2026-70492 (open-webui) — CWE-79 / CVSS v3 8.7
Attack vector: remote (network-reachable)
Attack surface: catch / RangeError / onerror / localStorage.token
Patched: 0.11.0 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
Cross-site scripting (XSS) (CWE-79) exists in open-webui. Attackers reach the vulnerable code path via catch.
Check the vendor advisory for the affected versions of open-webui. Attack surface: catch / RangeError / onerror / localStorage.token.
Severity: High (CVSS 8.7/10). Confidential information can be exposed externally.
Update to 0.11.0.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'open-webui' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
grep -r 'open-webui' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
open-webuiを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade open-webui to 0.11.0ステージング環境で 0.11.0 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
-
3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
References
- advisory github.com
- advisory github.com
- advisory nvd.nist.gov
- advisory github.com
- package github.com
- package pypi.org
- patch github.com
- patch github.com
- web github.com