What happened
Open WebUI is an extensible, feature-rich, and user-friendly self-hosted AI platform. From 0.8.0 until 0.11.0, when ENABLE_OAUTH_TOKEN_EXCHANGE=True, /oauth/{provider}/token/exchange accepts a raw provider access token and validates it by calling the provider userinfo endpoint without confirming which OAuth client the token was issued to. Anyone holding an access token minted for any client registered with the same provider could exchange it for an Open WebUI session as that token user, including applications the operator does not control and has never authorized. This issue is fixed in 0.11.0.
Affected versions
open-webui: >= 0.8.0, < 0.11.0 Fixed: See vendor advisory.
Why it matters
Review the vendor advisory and exposure of the affected product to determine operational impact.
Detection & mitigation
- Apply vendor-provided updates or mitigations.
- Review affected product exposure and access logs.