CVE-2026-44557: open-webui Incorrect Authorization

Vulnerability summary

CVE-2026-44557 is a medium (CVSS 4.3) Incorrect Authorization vulnerability in open-webui. EPSS estimates a 0.30% chance of exploitation in the next 30 days, higher than 21.9% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 15-05-2026
   PublishedVulnerability first disclosed.
2. 18-05-2026
   Last modifiedVulnerability information updated.

Description

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.0, the _validate_collection_access function uses an incomplete allowlist that only enforces ownership checks for collections matching user-memory-* and file-* patterns. All other collection names pass through unchecked — including the system-level knowledge-bases meta-collection, which stores the IDs, names, and descriptions of every knowledge base on the instance. Any authenticated user can query this meta-collection directly via the retrieval query endpoints to obtain a global index of all knowledge bases across all users. This vulnerability is fixed in 0.9.0.

• CWE-863Incorrect AuthorizationThe product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.