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High

Open WebUI's responses passthrough endpoint lacks access control authorization

  • Disclosed: 08.05.2026
  • Updated: 11.10.2026 14:18

Summary

The /responses endpoint in the OpenAI router accepts any authenticated user and forwards requests directly to upstream LLM providers without enforcing per-model access control. While the primary chat completion endpoint (generate_chat_completion) checks model ownership, group membership, and AccessGrants before allowing a request, the /responses proxy only validates that the user has a valid session via get_verified_user.

This allows any authenticated user — regardless of role or group assignment — to interact with any model configured on the instance by sending a POST request to /api/openai/responses with an arbitrary model ID.

Impact

As per OWASP TOP 10 LLM:

  • Model Denial of Service (OWASP LLM04): An unauthorized user can submit resource-intensive requests to expensive models (e.g., o1-pro, GPT-4o) that were explicitly restricted by the administrator. In shared deployments, this can exhaust API budgets or rate limits, causing total service disruption for all legitimate users.

  • Model Theft (OWASP LLM10): If the instance proxies access to fine-tuned or self-hosted models, unauthorized users can freely interact with them, enabling capability extraction or model distillation without authorization.

  • Access Policy Bypass: Administrators lose the ability to enforce cost-tier restrictions, team-based model assignments, or compliance boundaries through the existing access control system.

The endpoint is a raw passthrough proxy and does not resolve workspace model configurations (system prompts, knowledge bases, RAG pipelines). Therefore, workspace-specific confidential data is not directly exposed through this vector.

PR: https://github.com/open-webui/open-webui/pull/23481

Affected software

Click a technology to see all vulnerabilities affecting it.

PlatformPackageVulnerable versionsFixed in
Python (PyPI) open-webui < 0.9.0 0.9.0

References

CVSS score 7.1/10
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H
Weakness (CWE)
CWE-284, CWE-862
Platform
Python (PyPI)
Package
open-webui
Disclosed
08.05.2026
Updated
11.10.2026 14:18

Sources and licenses

OSV / GitHub Advisory Database - PYSEC-2026-2734 - PyPA Advisory Database; CC BY 4.0

OSV / GitHub Advisory Database - GHSA-hp5m-24vp-vq2q - CC BY 4.0

Vulnerability history: open-webui

All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.

All (161) in the archive
Total entries
161
First → latest
08.2024 09.2026
Without a fix
11
Exploited in attacks
0

Severity breakdown

  • Critical 1
  • High 77
  • Medium 75
  • Low 8

Disclosures per year

Severity:
  1. Open WebUI: Unauthenticated requests can stall the server via uncached OIDC fetches in back-channel logout
    High · 7.5 CVE-2026-87011 >= 0.9.0, < 0.11.1 0.11.1
  2. Open WebUI: Sign-in as another user via wildcard characters in the OAuth subject claim on SQLite
    High · 8.1 CVE-2026-87016 >= 0.6.41, < 0.11.1 0.11.1
  3. Open WebUI: Same-origin XSS to account takeover via terminal port-preview iframe hardcoding allow-same-origin
    High · 8.7 CVE-2026-87995 >= 0.8.11, < 0.11.1 0.11.1
  4. Open WebUI: SSRF into internal services via DNS rebinding in the Playwright web loader
    High · 7.7 CVE-2026-87996 >= 0.9.6, < 0.11.1 0.11.1
  5. Open WebUI: Non-admin users can delete admin-owned external knowledge connections via knowledge base deletion
    High · 7.1 CVE-2026-87998 >= 0.10.0, < 0.11.1 0.11.1
  6. Open WebUI: Any authenticated user can reach the Azure platform channel via server-side web fetch
    High · 7.1 CVE-2026-87999 < 0.11.1 0.11.1
  7. Open WebUI: A folder write-collaborator can permanently delete the owner's chats by deleting a shared subfolder
    High · 8.1 CVE-2026-70494 >= 0.10.0, < 0.11.0 0.11.0
  8. Open WebUI: Stored XSS via unescaped KaTeX render-error fallback in rendered messages
    High · 8.7 CVE-2026-70492 >= 0.10.0, < 0.11.0 0.11.0
  9. Open WebUI: Same-origin XSS to account takeover via terminal file-preview iframe hardcoding allow-same-origin
    High · 8.2 CVE-2026-70486 >= 0.9.0, < 0.11.0 0.11.0
  10. Open WebUI: Any authenticated user can reach internal services and cloud metadata via NAT64-encoded URLs
    High · 7.1 CVE-2026-70485 >= 0.9.0, < 0.11.0 0.11.0
  11. Open WebUI: Account takeover via OAuth token exchange accepting tokens issued to any client
    High · 8.1 CVE-2026-70482 >= 0.8.0, < 0.11.0 0.11.0
  12. Open WebUI: SSRF into internal services via unvalidated sub-resource requests in the Playwright web loader
    High · 7.7 CVE-2026-70479 >= 0.9.6, < 0.11.0 0.11.0
  13. open-webui terminal proxy path traversal guard bypass via 9x encoded traversal
    High · 7.7 CVE-2026-59221 >= 0.9.6, < 0.10.0 0.10.0
  14. Open WebUI: Terminal proxy forwards a spoofable, integrity-unbound user identity to the upstream (X-User-Id header and ws_terminal session_id query injection)
    High · 8.0 CVE-2026-59224 < 0.10.0 0.10.0
  15. Open WebUI: Cross-user code-interpreter and tool execution via unvalidated Socket.IO event-caller session_id
    High · 7.7 CVE-2026-59216 < 0.10.0 0.10.0
  16. Open WebUI: Cross-channel message overwrite via chat completion API (single-model and multimodel message_ids)
    High · 7.1 CVE-2026-59714 >= 0.9.5, < 0.10.0 0.10.0
  17. Open WebUI: Realtime endpoints accept Redis-revoked JWTs after signout/backchannel logout
    High · 7.1 CVE-2026-59219 >= 0.9.0, < 0.10.0 0.10.0
  18. Open WebUI: Stored web worker XSS via Pyodide
    High · 7.3 CVE-2026-59214 < 0.10.0 0.10.0
  19. Open WebUI vulnerable to Stored XSS via iFrame embeds in response messages
    High · 7.3 CVE-2026-26193 < 0.6.44 0.6.44
  20. Open WebUI vulnerable to Stored XSS via iFrame in citations model
    High · 7.3 CVE-2026-26192 < 0.7.0 0.7.0
  21. Open WebUI vulnerable to stored XSS via unescaped markdown token in MarkdownTokens.svelte leading to full account takeover and RCE via functions
    High CVE-2025-46719 < 0.6.6 0.6.6
  22. Open WebUI: SSRF Protection Bypass in Playwright Web Loader via HTTP Redirects
    High · 7.7 CVE-2026-54018 < 0.9.6 0.9.6
  23. Open WebUI: Path traversal / SSRF in terminal server proxy via encoded path traversal
    High · 7.7 CVE-2026-54017 < 0.9.6 0.9.6
  24. Open WebUI: Stored XSS to Account Takeover via Model Profile Images
    High · 7.6 CVE-2026-54013 < 0.9.6 0.9.6
  25. Open WebUI: Forged model meta.knowledge allows cross-user file read and deletion
    High · 7.1 CVE-2026-54012 < 0.9.6 0.9.6
  26. Open WebUI: Stored XSS in Mermaid Markdown Preview
    High · 8.7 CVE-2026-54011 < 0.9.6 0.9.6
  27. Open WebUI: Forged chat-file link allows cross-user file read and deletion
    High · 8.3 CVE-2026-54010 < 0.9.6 0.9.6
  28. Open WebUI: Redirect-Bypass SSRF in OAuth `_process_picture_url` (incomplete-fix sibling of CVE-2026-45401)
    High · 8.5 CVE-2026-54008 < 0.9.6 0.9.6
  29. Open WebUI: Cross-origin postMessage confirmation bypass via action:submit
    High · 6.5 CVE-2026-54007 < 0.9.6 0.9.6
  30. Open WebUI: LDAP and OAuth First-User Race Condition Allows Multiple Admin Accounts
    High · 8.1 CVE-2026-45675 < 0.9.0 0.9.0
  31. Open WebUI: Jupyter code execution works despite `ENABLE_CODE_EXECUTION=false` — feature gate bypassed
    High · 8.8 CVE-2026-45672 < 0.8.12 0.8.12
  32. Open WebUI: shared-chat branch ignores access_type, allowing unauthorized file deletion
    High · 8.0 CVE-2026-45671 < 0.9.0 0.9.0
  33. Open WebUI: Cross-User File Access via Unchecked file_id in Folder Knowledge and Knowledge-Base Attach Endpoints
    High · 8.1 CVE-2026-45402 < 0.9.5 0.9.5
  34. Open WebUI vulnerable to stored XSS via OAuth picture claim stored as SVG data URI in profile_image_url
    High · 7.3 CVE-2026-56398 < 0.9.5 0.9.5
  35. Open WebUI has a SSRF Bypass via HTTP Redirect Following in Web-Fetch and Image-Load Endpoints (not addressed by CVE-2025-65958)
    High · 8.5 CVE-2026-45401 < 0.9.5 0.9.5
  36. Open WebUI has a Server-Side Request Forgery (SSRF) bypass in `validate_url`
    High · 8.5 CVE-2026-45400 < 0.9.5 0.9.5
  37. Open WebUI: Low-privilege authenticated users can enumerate and stop global background tasks, causing system-wide chat disruption
    High · 7.1 CVE-2026-45399 < 0.9.0 0.9.0
  38. Open WebUI Vulnerable to IDOR: Retrieval API Bypasses Knowledge Base Access Controls
    High · 7.5 CVE-2026-45398 < 0.9.5 0.9.5
  39. Open WebUI's chat completion API allows tool restrictions to be bypassed
    High · 7.1 CVE-2026-45350 < 0.8.6 0.8.6
  40. Open WebUI has Broken Access Control for Completions API
    High · 7.1 CVE-2026-45349 < 0.9.0 0.9.0
  41. Open WebUI Vulnerable to SSRF via OAuth Profile Picture URL in _process_picture_url (oauth.py)
    High · 7.7 CVE-2026-45338 < 0.9.0 0.9.0
  42. Open WebUI has a full SSRF Vulnerability in the RAG Web Search Feature
    High · 8.5 CVE-2026-45331 < 0.9.0 0.9.0
  43. Open WebUI has XSS via SVG in /api/v1/channels/webhooks/{webhook_id}/profile/image
    High · 6.1 CVE-2026-45314 < 0.9.3 0.9.3
  44. Open WebUI has stored XSS via attacker-controlled file extension in /api/v1/audio/transcriptions
    High · 8.7 CVE-2026-45315 < 0.9.3 0.9.3
  45. Open WebUI has stored XSS via the HTML renedering view
    High · 7.7 CVE-2026-45303 < 0.6.5 0.6.5
  46. Open WebUI: Missing permission check in files API allows authenticated users to list, access and delete every uploaded file
    High · 8.1 CVE-2026-45301 < 0.3.16 0.3.16
  47. Open WebUI has inconsistent authorization controls within memories API
    High · 8.3 CVE-2026-44570 < 0.6.19 0.6.19
  48. Open WebUI's Insecure Message Access Breaks Authorization
    High · 7.1 CVE-2026-44569 < 0.6.19 0.6.19
  49. Open WebUI Arbitrary File Write, Delete via Path Traversal
    High · 8.1 CVE-2026-44565 < 0.6.10 0.6.10
  50. Open WebUI has a CORS misconfiguration and session validation issue
    High · 8.3 CVE-2026-56400 < 0.3.33 0.3.33
  51. Open WebUI Vulnerable to Arbitrary File Upload and Path Traversal
    High · 7.3 CVE-2026-44566 < 0.1.124 0.1.124
  52. Open WebUI has Improper Authorization Control
    High · 7.3 CVE-2026-44567 < 0.1.124 0.1.124
  53. Open WebUI has stored XSS in Excel file preview
    High · 7.3 CVE-2026-44549 < 0.8.0 0.8.0
  54. Open WebUI has Knowledge Base Destruction and RAG Poisoning via Unauthorized Collection Overwrite
    High · 8.1 CVE-2026-44554 < 0.9.0 0.9.0
  55. Open WebUI's responses passthrough endpoint lacks access control authorization this entry
    High · 7.1 CVE-2026-44556 < 0.9.0 0.9.0
  56. Open WebUI's Base Model Routing Bypasses Access Control via Model Chaining
    High · 7.6 CVE-2026-44555 < 0.9.0 0.9.0
  57. Open WebUI: Redis Cache Keys tool_servers and terminal_servers Missing Instance Prefix Enable Cross-Instance Cache Poisoning
    High · 8.7 CVE-2026-44552 < 0.9.0 0.9.0
  58. Open WebUI: Stale Admin Role in Socket.IO Session Pool Enables Post-Demotion Cross-User Note Access
    High · 8.1 CVE-2026-44553 < 0.9.0 0.9.0
  59. Open WebUI has an LDAP Empty Password Authentication Bypass
    Critical · 9.1 CVE-2026-44551 < 0.9.0 0.9.0
  60. open-webui Vulnerable to Stored XSS via Model Description
    High · 7.3 CVE-2026-44721 < 0.9.0 0.9.0
Show more (18) Showing 60 of 78

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