Open WebUI Access Control and File Handling

Open WebUI versions prior to 0.8.6 permit authenticated users to overwrite arbitrary file contents through an insecure batch processing endpoint, escalating read-only knowledge base access to write permissions without ownership validation. Attackers with low-level privileges can manipulate RAG (Retrieval-Augmented Generation) content served to language models, poisoning AI responses delivered to other users. CVSS 7.1 (High) reflects network-accessible exploitation with low complexity requiring only standard user authentication; no public exploit identified at time of analysis.

Open WebUI versions prior to 0.8.6 allow authenticated users to delete arbitrary files from knowledge bases they have write access to, due to missing validation that files actually belong to the target knowledge base. An attacker with legitimate write permissions to any knowledge base can exploit this to delete files from other knowledge bases by crafting requests with known file identifiers, resulting in data loss and service disruption. No public exploit code or active exploitation has been reported at time of analysis.

Open WebUI versions prior to 0.8.6 disclose the server's absolute DATA_DIR path to any authenticated non-admin user via unsanitized filename handling in the speech-to-text transcription endpoint, which returns FileNotFoundError messages in HTTP 400 responses. This information disclosure affects all default deployments and requires only user-level authentication to trigger. The vulnerability has been patched in version 0.8.6, and no public exploit code or active exploitation has been identified at time of analysis.

Open WebUI versions prior to 0.8.6 allow authenticated users to read other users' private memories through an insufficiently restricted API endpoint at `/api/v1/retrieval/query/collection`, exposing sensitive user data stored within the self-hosted AI platform. The vulnerability requires valid authentication credentials and carries a CVSS score of 3.1 with low attack complexity, indicating limited real-world exploitability despite the information disclosure impact. No public exploit code or active exploitation has been confirmed at the time of analysis.