CVE-2026-55873: SeaweedFS: Improper authorization in the S3Tables / Iceberg REST management API lets a low-privileged S3 user enumerate administrator-owned table buckets

Summary SeaweedFS routes requests signed with SigV4 service s3tables to the S3Tables management API. Authorization on that path collapsed account-less S3 identities into the shared admin account and failed open, so a user holding only ordinary S3 Read credentials — and no S3Tables-specific permission — could invoke S3Tables management operations such as GET /buckets and enumerate administrator-owned table bucket inventory (names and ARNs). The same handler backs the Iceberg REST catalog, which was affected by the same flaw.

Impact An authenticated low-privileged S3 user can cross the boundary between ordinary S3 object access and S3Tables management. Confirmed impact is disclosure of administrator-owned table bucket inventory (bucket names and ARNs); in shared or multi-tenant deployments this can reveal tenant naming and operational structure.

Affected versions SeaweedFS >= 4.08, < 4.34 (the S3Tables management API was introduced in 4.08).

Patched versions Fixed in 4.34 (#9961). Administrator status is now decided by the ACTIONADMIN capability rather than by a collapsed admin account id, S3Tables authorization no longer defaults to allow, and the tautological ListTableBuckets gate was removed. Related hardening of the same root cause landed in #9962, #9963, and #9971.

Workaround No configuration workaround — upgrade to 4.34 or later.

Credit Reported by TA-MU-TA.