CVE-2026-54021: Open WebUI proxy bypass routes calls to arbitrary Ollama backends

# CVE-2026-54021: Open WebUI proxy bypass routes calls to arbitrary Ollama backends

https://gcdradar.vercel.app/incidents/cve-2026-54021-open-webui-proxy-bypass-routes-calls-to-arbit · AIR-2026-0756 · closed 2026-06-17

- Lane: Patch now
- Severity: 2 (Disclosed vulnerability)
- Fix status: Fix status unknown
- First reported: 2026-06-17
- AI role: Attack on AI
- Products: Open WebUI, Ollama
- CVE ids: CVE-2026-54021
- CVSS: 6.3

## Summary

Direct indexed Ollama proxy routes failed to validate backend authorization against requested indices, letting authenticated users access internal backends. The vulnerability exposes unauthorized higher-privilege or restricted Ollama instances.

## What to do

No action recorded; read the sources below and the vendor's advisory.

## Latest updates

- 2026-06-23: CVE-2026-54021: Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. (https://nvd.nist.gov/vuln/detail/CVE-2026-54021)
- 2026-06-17: CVE-2026-54021: Open WebUI: Authenticated users can target arbitrary configured Ollama backends via unguarded url_idx path parameter (https://github.com/advisories/GHSA-9rpj-v7hf-vv2w)

## Sources

- 2026-06-17 GitHub Advisory Database: CVE-2026-54021: Open WebUI: Authenticated users can target arbitrary configured Ollama backends via unguarded url_idx path parameter https://github.com/advisories/GHSA-9rpj-v7hf-vv2w
- 2026-06-23 NVD: CVE-2026-54021: Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. https://nvd.nist.gov/vuln/detail/CVE-2026-54021

Verify against the vendor's advisory before changing production. Data CC BY-SA 4.0, https://gcdradar.vercel.app.