Critical [CVE-2026-42812] In Apache Iceberg, the table's metadata files are control files: they tell readers which data files belong to the table and

In Apache Iceberg, the table's metadata files are control files: they tell readers which data files belong to the table and which table version to read.

`write.metadata.path` is an optional table property that tells Polaris where to

write those metadata files. For a table already registered in a

Polaris-managed catalog, changing only that property through an `ALTER TABLE`-style settings

change (not a row-level `INSERT`, `SELECT`, `UPDATE`, or `DELETE`) bypasses the commit-time branch that is supposed to revalidate storage locations.

The full persisted / credential-vending variant requires the affected to have `polaris.config.allow.unstructured.table.location=true`, with

`allowedLocations` broad enough to include the attacker-chosen target.

`allowedLocations` is the admin-configured allowlist of storage paths that catalog is allowed to use.

Public project materials suggest that this flag is a

real supported compatibility / layout mode, not just a contrived lab-only prerequisite.

In that configuration, a user who can change table settings can cause Apache Polaris itself to write new table metadata to an attacker-chosen reachable storage

location before the intended location-validation branch runs.

If the later concrete-path validation also accepts that location, Polaris persists the resulting metadata path into stored table state.

table-load