What is CVE-2026-73334?

CVE-2026-73334 is a high-severity vulnerability in Apache Parquet, classified under Improper Input Validation. CVSS score: 8.1/10. Published 2026-09-09.

How severe is CVE-2026-73334?

High severity. CVSS v3 base score is 8.1 out of 10.

Improper input validation in Apache Parquet

CVE-2026-73334

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.

Vulnerability class: Drupalgeddon 2 (CVE-2018-7600)

Published 2026-09-09 · last modified 2026-09-10.

CVSS v3 metric

CVSS v3 base score 8.1 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N.

EPSS exploit prediction

EPSS: 0.004 (28.7th percentile), scored 2026-10-24.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 29th percentile — 28.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: 0.000

Affected products

Weakness classification (CWE)

CWE-20 — Improper Input Validation

References

lists.apache.org/thread/ro2vomk9xxhv34xhvopgys96c9j8ojm0 (vendor-advisory, Mailing List, Vendor Advisory)
af854a3a-2127-422b-91ae-364da2661108 (Mailing List, Third Party Advisory)

Frequently asked questions

What is CVE-2026-73334?: CVE-2026-73334 is a high-severity vulnerability in Apache Parquet, classified under Improper Input Validation. CVSS score: 8.1/10. Published 2026-09-09.
How severe is CVE-2026-73334?: High severity. CVSS v3 base score is 8.1 out of 10.