Open WebUI: Cross-user file disclosure via /api/chat/completions image_url field
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- High · None · None
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-639.
Summary
Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.6, POST /api/chat/completions accepts an image_url.url value that, when it does NOT start with http://, https://, or data:image/, is interpreted as a file id and resolved against the global file table with no ownership check. an authenticated user can therefore set image_url.url to another user's file id, the server reads that file from disk, base64-encodes it, and injects the data URI into the LLM request. the user then prompts the LLM to describe / OCR the file and reads the content back. This vulnerability is fixed in 0.9.6.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- No
- Technical impact
- Partial
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 | before 0.9.6 | 0.9.6 | Patch available | CNA |
| — | open-webui (PyPI) | before 0.9.6 | 0.9.6 | Patch available | GHSA-wch8-mhj5-9frg |
- open-webui Vendoropen-webui Affected before 0.9.6 Fixed in 0.9.6 Patch available CNA
- open-webui (PyPI) Vendor— Affected before 0.9.6 Fixed in 0.9.6 Patch available GHSA-wch8-mhj5-9frg
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:openwebui:open_webui:*:*:*:*:*:*:*:* | before 0.9.6 | Vulnerable | open-webui |
- cpe:2.3:a:openwebui:open_webui:*:*:*:*:*:*:*:* Versions before 0.9.6 Vulnerable ·open-webui
Remediation
- Fix · CNA open-webui (open-webui) Fixed in 0.9.6
- Fix · GHSA-wch8-mhj5-9frg open-webui (PyPI) Fixed in 0.9.6 Advisory →
Timeline
- 2026-10-02 Threatist record created from CVE-2026-54009
- 2026-10-03 Alias added: GHSA-wch8-mhj5-9frg
References
Advisory 2
More open-webui 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-2026-54009 · CVE Program
- CVE-2026-54009 · NVD
- FIRST EPSS
- GHSA-wch8-mhj5-9frg · GitHub Advisory Database · CC BY 4.0
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