CVE-2025-55039 Apache Spark has Inadequate Encryption Strength

What is CVE-2025-55039?

CVE-2025-55039 is a medium-severity vulnerability in Apache Spark, published on 15 Oct 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

This issue affects Apache Spark versions before 3.4.4, 3.5.2 and 4.0.0.

Apache Spark versions before 4.0.0, 3.5.2 and 3.4.4 use an insecure default network encryption cipher for RPC communication between nodes.

When spark.network.crypto.enabled is set to true (it is set to false by default), 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 vulnerability 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.

To mitigate this issue, users should either configure spark.network.crypto.cipher to AES/GCM/NoPadding to enable authenticated encryption or

enable SSL encryption by setting spark.ssl.enabled to true, which provides stronger transport security.

Weakness: CWE-347, CWE-326

Which versions are affected by CVE-2025-55039?

13 open source packages ship an affected version, including org.apache.spark:spark-network-common_2.12, org.apache.spark:spark-network-common_2.13 and pyspark. It affects 1 product.

Products include Apache Spark.

How do I fix CVE-2025-55039?

Upgrade org.apache.spark:spark-network-common_2.12 to a fixed version for your release line: 3.4.4 or 3.5.2.

Is CVE-2025-55039 being exploited?

There is no known exploitation of CVE-2025-55039 in the wild and no public exploit code.

Other vulnerabilities in Apache Spark

• CVE-2022-33891 Apache Spark Command Injection Exploited High 8.8
• CVE-2020-9480 Improper Authentication in Apache Spark Critical 9.8
• CVE-2018-17190 Remote Code Execution in spark-core Critical 9.8
• CVE-2019-20445 HTTP Request Smuggling in Netty Critical 9.1
• CVE-2025-54920 Apache Spark: Spark History Server Code Execution Vulnerability High 8.8

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-6p6v-m64v-jx8q, PYSEC-2025-184.