What’s Vulnerable › Vulnerabilities
CVE-2026-54021: Open WebUI: Authenticated users can target arbitrary configured Ollama backends via unguarded url_idx path parameter
- Severity: medium (CVSS 6.3 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.3% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-06-23 · updated 2026-06-26
- Weakness: CWE-863
Description
Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.6, several direct, index-addressed Ollama proxy routes accept a caller-supplied url_idx path parameter and use it as a raw index into the admin-configured OLLAMA_BASE_URLS list. Access control on these routes validates only whether the user may use the requested model, never which backend the request is routed to. Any authenticated user can append an arbitrary url_idx to force their request onto an Ollama backend they were never authorized to reach, including internal, higher-privilege, or explicitly admin-disabled backends. This vulnerability is fixed in 0.9.6.
Affected products
- open-webui: before 0.9.6 — fixed in 0.9.6
How to fix
Upgrade to a fixed version: open-webui 0.9.6. Check the vendor advisory for mitigations.
References
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