An attacker who can alter a table’s settings via an ALTER TABLE statement in Apache Polaris can change the optional write.metadata.path property, causing Polaris to write metadata files to an arbitrary storage location without performing the intended pre‑write location validation. The vulnerability bypasses the commit‑time branch that normally revalidates storage paths, enabling the system to persist metadata to a user‑chosen path that may be outside the allowedLocations list. This flaw can lead to the issuance of temporary cloud‑storage credentials for arbitrary directories or buckets, allowing an attacker to read, modify, or delete data and metadata within that scope, effectively leaking or corrupting sensitive information stored in the target location.

Apache Polaris, a component of the Apache Iceberg ecosystem, is affected when the polaris.config.allow.unstructured.table.location flag is set to true and the allowedLocations allowlist contains the attacker‑chosen target. Even when the flag is false, the underlying defect remains because the system still skips pre‑write location checks when write.metadata.path changes, although the broader risk is reduced by the later validation step.

The CVSS score of 9.4 indicates a high‑severity risk, and while EPSS is not available, the absence of a KEV listing means that no confirmed exploitation has been documented. The likely attack vector involves privileged users executing an ALTER TABLE to modify write.metadata.path; the vulnerability is exploitable from within the Polaris deployment, requiring only that the attacker have permission to alter table properties. The resulting ability to write metadata to arbitrary locations and hand out credentials can lead to compromise of large storage prefixes or complete buckets, posing a significant confidentiality and integrity threat.