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
catalog
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
the
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. Later
table-load
and credential APIs can then return temporary cloud-storage credentials for
the
same location without revalidating it. In plain terms, Polaris can later
hand
out temporary storage access for the same attacker-chosen area.

That attacker-chosen area does not need to be limited to the poisoned
table's
own files. If it is a broader storage prefix, another table's prefix, or,
depending on configuration or provider behavior, even a bucket/container
root,
the resulting disclosure or corruption scope can extend to any data and
metadata Polaris can reach there.



The practical consequences are therefore similar to the staged-create
credential-vending issue already discussed: data and metadata reachable in
that
storage scope can be exposed and, if write-capable credentials are later
issued, modified, corrupted, or removed. Even before that later credential
step, Polaris itself performs the metadata write to the unchecked location.

So the core issue is not only later credential vending.

The primary defect
is
that Polaris skips its intended location checks before performing a
security-
sensitive metadata write when only `write.metadata.path` changes.



When `polaris.config.allow.unstructured.table.location=false`, current code
review suggests the later `updateTableLike(...)` validation usually rejects
out-of-tree metadata locations before the unsafe path is persisted. That may
reduce the persisted / credential-vending variant, but it does not prevent
the
underlying defect: Polaris still skips the intended pre-write location check
when only `write.metadata.path` changes.

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Fixes

Solution

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Workaround

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History

Mon, 04 May 2026 20:15:00 +0000

Type Values Removed Values Added
First Time appeared Apache
Apache polaris
Vendors & Products Apache
Apache polaris

Mon, 04 May 2026 17:30:00 +0000

Type Values Removed Values Added
References

Mon, 04 May 2026 17:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}


Mon, 04 May 2026 16:30:00 +0000

Type Values Removed Values Added
Description 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 catalog 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 the 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. Later table-load and credential APIs can then return temporary cloud-storage credentials for the same location without revalidating it. In plain terms, Polaris can later hand out temporary storage access for the same attacker-chosen area. That attacker-chosen area does not need to be limited to the poisoned table's own files. If it is a broader storage prefix, another table's prefix, or, depending on configuration or provider behavior, even a bucket/container root, the resulting disclosure or corruption scope can extend to any data and metadata Polaris can reach there. The practical consequences are therefore similar to the staged-create credential-vending issue already discussed: data and metadata reachable in that storage scope can be exposed and, if write-capable credentials are later issued, modified, corrupted, or removed. Even before that later credential step, Polaris itself performs the metadata write to the unchecked location. So the core issue is not only later credential vending. The primary defect is that Polaris skips its intended location checks before performing a security- sensitive metadata write when only `write.metadata.path` changes. When `polaris.config.allow.unstructured.table.location=false`, current code review suggests the later `updateTableLike(...)` validation usually rejects out-of-tree metadata locations before the unsafe path is persisted. That may reduce the persisted / credential-vending variant, but it does not prevent the underlying defect: Polaris still skips the intended pre-write location check when only `write.metadata.path` changes.
Title Apache Polaris: No protection on `write.metadata.path`
Weaknesses CWE-20
CWE-284
CWE-732
CWE-863
References
Metrics cvssV3_1

{'score': 9.9, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H'}

cvssV4_0

{'score': 9.4, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: apache

Published:

Updated: 2026-05-04T16:38:57.660Z

Reserved: 2026-04-30T14:36:55.718Z

Link: CVE-2026-42812

cve-icon Vulnrichment

Updated: 2026-05-04T16:38:57.660Z

cve-icon NVD

Status : Received

Published: 2026-05-04T17:16:26.887

Modified: 2026-05-04T17:16:26.887

Link: CVE-2026-42812

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-05-04T19:44:04Z