CVE-2026-42810 Apache Polaris: could broaden vended S3 credentials through wildcard-bearing namespace or table names

Critical 9.4 Published 4 May 2026 Updated 4 May 2026

Attackers can craft wildcard table names to obtain S3 credentials granting unauthorized read and write access to other tables' data.

Exploited in the wild: Not known
Login needed: Any signed-in user
Attackable: Over the internet
Victim action needed: Not needed
Fix: Available

What is CVE-2026-42810?

CVE-2026-42810 is a critical vulnerability in Apache Polaris, published on 4 May 2026. Any signed-in user can exploit it over the network, with no action from the victim.

Official description

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 and `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 and deleting an object under another table's exact S3 table prefix.

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 setup, direct Polaris access to `foo.t1` remained forbidden, but the attacker could still create and load `*.*`, receive delegated S3 credentials, and use those credentials to list, read, create, and delete objects under `foo.t1`.

In Iceberg, the metadata JSON file is a control file: it tells readers which data files belong to the table, which snapshots exist, and which table version to read. So unauthorized access to it is already a meaningful confidentiality problem. The confirmed write-capable variant means the issue is not limited to disclosure.

Weakness: CWE-20, CWE-116

Which versions are affected by CVE-2026-42810?

2 open source packages ship an affected version, including org.apache.polaris:polaris-core. It affects 1 product.

Package	Affected	Fixed in
`org.apache.polaris:polaris-core` Maven	All versions	`1.4.1`
`org.apache.polaris:polaris-core` Maven	All versions	`1.4.1`

Products include Apache Polaris.

How do I fix CVE-2026-42810?

Upgrade org.apache.polaris:polaris-core to 1.4.1 or later.

Is CVE-2026-42810 being exploited?

There is no known exploitation of CVE-2026-42810 in the wild and no public exploit code.

Sources

Also known as GHSA-vxgg-mqx2-3w59.