Critical [CVE-2026-42810] Apache Polaris: Apache Polaris accepts literal `*` characters in namespace and table names.

Apache Polaris accepts literal `*` characters in namespace and table names. When it

later builds temporary S3 access policies for delegated table access, those same characters appear to be reused unescaped in S3 IAM resource patterns

`s3:prefix` conditions.

In S3 IAM policy matching, `*` is treated as a wildcard rather than as ordinary text.

That means temporary credentials issued for one crafted table can match the storage path of a different table.

In private testing against Polaris 1.4.0 using Polaris' AWS S3 temporary- credential path on both MinIO and real AWS S3, credentials returned for

crafted tables such as `f*.t1`, `f*.*`, `*.*`, and `foo.*` could reach other tables' S3 locations.

The confirmed behavior includes:

• reading another table's metadata control file ([Iceberg metadata JSON]);
• listing another table's exact S3 table prefix ([table prefix]);
• and, when write delegation was returned for the crafted table, creating

A control case using ordinary different names did not allow the same cross-table access.

A least-privilege AWS S3 variant was also confirmed in which the attacker principal had no Polaris permissions on the victim table and only the

minimal permissions required to create and use a crafted wildcard table (namespace-scoped `TABLE_CREATE` and `TABLE_WRITE_DATA` on `*`).

In that