CVE-2023-22946: Apache Spark proxy-user privilege escalation from malicious configuration class

Severity: critical (CVSS 9.9 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-04-17 · updated 2026-06-17
Weakness: CWE-269

Description

In Apache Spark versions prior to 3.4.0, applications using spark-submit can specify a 'proxy-user' to run as, limiting privileges. The application can execute code with the privileges of the submitting user, however, by providing malicious configuration-related classes on the classpath. This affects architectures relying on proxy-user, for example those using Apache Livy to manage submitted applications. Update to Apache Spark 3.4.0 or later, and ensure that spark.submit.proxyUser.allowCustomClasspathInClusterMode is set to its default of "false", and is not overridden by submitted applications.

Affected products

Apache Software Foundation Apache Spark: before 3.4.0 — fixed in 3.4.0

How to fix

Upgrade to a fixed version: Apache Software Foundation Apache Spark 3.4.0. Check the vendor advisory for mitigations.

References

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