Missing collaborator checks in Mathesar 0.2.0 through 0.9.x allow an authenticated user to request database‑level metadata for databases where they are not collaborators. The endpoints collaborators.list, tables.metadata.list, explorations.list, and forms.list accept a database_id without verifying collaborator status. Exposed metadata can include collaborator mappings, table metadata, saved exploration data, and form metadata. For public forms, the metadata also contains form tokens, which are equivalent to public form links and enable form submission under the configured PostgreSQL role.

The vulnerability affects the Mathesar web application provided by mathesar-foundation. Versions from 0.2.0 up to, but not including, 0.10.0 are susceptible. Version 0.10.0 and later contain the fix.

The CVSS score of 5.3 indicates moderate severity. EPSS is not available, and the vulnerability is not listed in the CISA KEV catalog, suggesting no widely published exploits yet. Because the bug requires an authenticated session, the likely attack vector involves an existing user exploiting allowed API calls to retrieve metadata that should be restricted to collaborators.