Stored XSS in Open WebUI citation embed_url lets attackers steal sessions
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- Passive
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- Cross-site scripting
- Confidentiality · integrity · availability
- High · High · None
- Fix status
- Fixed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-79.
Summary
Open WebUI from 0.6.33 before 0.11.4 contains a cross-site scripting flaw (CWE-79) in citation embed_url fields. An authenticated user can store javascript: URLs there, and a crafted shared chat passes the citation to window.open when clicked. A victim who clicks it can have the attacker's script run in their session and read localStorage.token, acting as the victim.
Written with Claude Haiku 5.5 from the sources below · 2026-10-29
Description from the CNA
Open WebUI from 0.6.33 before 0.11.4 contains a cross-site scripting vulnerability that allows authenticated users to execute script in victims' sessions by storing javascript: URLs in citation embed_url fields. Attackers can share a crafted chat whose citation, when clicked, is passed to window.open, letting them steal localStorage.token and act as the victim.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| open-webui | open-webui | 0.6.33 to before 0.11.4 | 0.11.4 | Patch available | CNA |
- open-webui Vendoropen-webui Affected 0.6.33 to before 0.11.4 Fixed in 0.11.4 Patch available CNA
CPE names Threatist (inferred) · 1
Inferred from how NVD named this product before; not given by a source.
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:openwebui:open_webui:*:*:*:*:*:*:*:* | — | — | open-webui |
- cpe:2.3:a:openwebui:open_webui:*:*:*:*:*:*:*:* Versions — — ·open-webui
Remediation
Upgrade Open WebUI to version 0.11.4, which fixes the flaw.
Written with Claude Haiku 5.5 from the sources below · 2026-10-29
- Fix · CNA open-webui (open-webui) Fixed in 0.11.4
Fixed in the same release
Records fixed by the same vendor advisory or release, as the CNA lists them.
- Release ·
open-webui 0.11.4
19 records Highest priority Priority HIGH 3 HIGH, 8 MEDIUM, 8 LOW
Other records, highest priority first
- TI-2026-71106 Stored cross-site scripting in Open WebUI via DOCX previewPriority HIGH 72
- TI-2026-71108 Session cookie disclosure in Open WebUI OAuth-mode connectionsPriority HIGH 68
- TI-2026-71104 Stored cross-site scripting in Open WebUI markdown linksPriority HIGH 67
Timeline
- 2026-10-12 Threatist record created from CVE-2026-109291
- 2026-10-12 Alias added: GHSA-g5hc-j8wv-8p98
- 2026-10-13 Priority changed: MEDIUM → LOW
- 2026-10-18 CISA SSVC decision points changed
References
More open-webui vulnerabilities
- TI-2024-06216 Open WebUI Arbitrary File Upload + Path Traversal CVSS 3.1HIGH 8.8
- TI-2024-07467 Improper Authentication in open-webui/open-webui CVSS 3.1HIGH 8.2
- TI-2026-42359 Open WebUI: Cross-user code-interpreter and tool execution via unvalidated Socket.IO event-caller session_id CVSS 3.1CRITICAL 9.0
- TI-2026-40759 open-webui - Remote Code Execution via CORS Misconfiguration and Session Validation CVSS 4.0CRITICAL 9.0
- TI-2024-07431 Cross-site Scripting (XSS) in open-webui/open-webui CVSS 3.0CRITICAL 9.0
- TI-2026-60021 Open WebUI: Same-origin XSS to account takeover via terminal port-preview iframe hardcoding allow-same-origin CVSS 3.1HIGH 8.7
Sources
- CVE-2026-109291 · CVE Program
- CVE-2026-109291 · NVD
- FIRST EPSS
- GHSA-g5hc-j8wv-8p98 · GitHub Advisory Database · CC BY 4.0
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