CVE-2025-55039

Name of the Vulnerable Software and Affected Versions Apache Spark versions prior to 3.4.4 Apache Spark versions prior to 3.5.2 Apache Spark versions prior to 4.0.0

Description Apache Spark versions before 3.4.4, 3.5.2, and 4.0.0 utilize an insecure default network encryption cipher for RPC communication between nodes. Specifically, when spark.network.crypto.enabled is set to true, but spark.network.crypto.cipher is not explicitly configured, Spark defaults to AES in CTR mode (AES/CTR/NoPadding), which provides encryption without authentication. This allows a man-in-the-middle attacker to modify encrypted RPC traffic undetected by flipping bits in ciphertext, potentially compromising heartbeat messages or application data and affecting the integrity of Spark workflows. The spark.network.crypto.cipher variable is used to configure the encryption cipher.

Recommendations Configure spark.network.crypto.cipher to AES/GCM/NoPadding to enable authenticated encryption. Enable SSL encryption by setting spark.ssl.enabled to true, which provides stronger transport security.