CVE-2026-42809: Apache Polaris: An authenticated low-privileged user can abuse Polaris staged table creation to mint broad temporary storage credentials for an attacker-chosen location before Polaris validates that location

[Jean-Baptiste Onofré <jbonofre () apache org>]

Severity: important 

Affected versions:

- Apache Polaris before 1.4.1

Description:

Apache Polaris can issue broad temporary ("vended") storage credentials during
staged
table creation before the effective table location has been validated or
durably reserved. 
Those temporary credentials are meant to limit the scope
of
accessible table data and metadata, but this scope limitation becomes
attacker-
directed because the attacker can choose a reachable target location.



In the confirmed variant, if the caller supplies a custom `location` during
stage create and requests credential vending, Apache Polaris uses that location to
construct delegated storage credentials immediately. The stage-create path
itself neither runs the normal location validation nor the overlap checks
before those credentials are issued.



Closely related to that, the staged-create flow also accepts
`write.data.path` / `write.metadata.path` in the request properties and
feeds
those location overrides into the same effective table location set used for
credential vending. Those fields are secondary to the main custom-`location`
exploit, but they are still attacker-influenced location inputs that should
be
validated before any credentials are issued.

References:

https://polaris.apache.org
https://www.cve.org/CVERecord?id=CVE-2026-42809