CVE-2026-73334 Apache Parquet Hadoop: File-controlled KMS URL is forwarded to pluggable KmsClient that skips host validation

High 8.1 Published 9 Sep 2026 Updated 10 Sep 2026

Attackers can send KMS tokens to malicious hosts via file-controlled URLs in Apache Parquet, potentially exposing sensitive keys if host validation is skipped.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: A user has to click or open something
Fix: Available

What is CVE-2026-73334?

CVE-2026-73334 is a high-severity server-side request forgery vulnerability in Apache Parquet Hadoop, published on 9 Sep 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

Official description

Potential problem for users of the org.apache.parquet.crypto.keytools package in Apache Parquet, versions 1.12 to 1.18. This package enables users to encrypt Parquet files via an envelope encryption mechanism that wraps (encrypts) data keys via a Key Management Service (KMS). On the reader side, the KMS URL can be application-controlled or file-controlled. If the user does not leverage application control for this parameter, a file-controlled KMS URL is forwarded to a pluggable KmsClient implementation. If the pluggable implementation does not perform host validation, a KMS token can be sent to a malicious host set by an attacker in the file.

Before the problem is fixed, users are recommended to leverage application control for KMS URL parameter in readers (versions 1.12-1.18). After the problem is fixed (presumably in version 1.19), the upgrade will disable file-controlled KMS URL by default. Users of the KMS URL parameter will have two options then: leverage application control for KMS URL parameter in readers, or enable file-controlled KMS URL (via a new app parameter). The latter option will explicitly require (in the new parameter documentation) to validate the KMS URL and use authentication in the custom implementation of the KMS client plug in.

Weakness: CWE-20

Which versions are affected by CVE-2026-73334?

It affects 1 product.

Products include Apache Parquet.

How do I fix CVE-2026-73334?

Upgrade to a fixed version.

Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.

Is CVE-2026-73334 being exploited?

There is no known exploitation of CVE-2026-73334 in the wild and no public exploit code.

CVE-2025-46762 Apache Parquet Java: Potential malicious code execution from trusted packages in the parquet-avro module when reading an Avro schema from a Parquet file metadata High 7.1

Sources

Also known as CLEANSTART-2026-AF89785, CLEANSTART-2026-MZ54004, GHSA-wrx6-qm3h-c589.