CVE-2026-85693: Chatbot UI Cross-User Private File Content Disclosure via Retrieval API

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-04 · updated 2026-09-24
Weakness: CWE-639

Description

Chatbot UI contains an authorization bypass vulnerability in the retrieval endpoint that allows authenticated attackers to access private file content belonging to other users by supplying arbitrary file UUIDs. The endpoint uses a service-role Supabase client that bypasses row-level security and fails to validate file ownership, enabling attackers to retrieve indexed content chunks from victim files through crafted POST requests.

References

https://github.com/mckaywrigley/chatbot-ui
https://github.com/mckaywrigley/chatbot-ui/blob/81328b61d2a4ab597a7a057be70e785cf756d9f8/app/api/retrieval/retrieve/route.ts
https://github.com/mckaywrigley/chatbot-ui/issues/2028
https://www.vulncheck.com/advisories/chatbot-ui-cross-user-private-file-content-disclosure-via-retrieval-api

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