Vulnerability · Published Oct 15, 2025 · Assigned by apache
CVE-2025-55039Apache Spark, Apache Spark: RPC encryption defaults to unauthenticated AES-CTR mode, enabling man-in-the-middle ciphertext modification attacks
Medium 6.5
In plain English
A medium-severity security flaw in Apache Spark from Apache Software Foundation. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 11% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Maven | org.apache.spark:spark-network-common_2.12 | 3.5.2 | GHSA-6p6v-m64v-jx8q |
| Maven | org.apache.spark:spark-network-common_2.12 | 3.4.4 | GHSA-6p6v-m64v-jx8q |
| Maven | org.apache.spark:spark-network-common_2.13 | 3.5.2 | GHSA-6p6v-m64v-jx8q |
| Maven | org.apache.spark:spark-network-common_2.13 | 3.4.4 | GHSA-6p6v-m64v-jx8q |
| PyPI | pyspark | 3.4.4, 3.5.2 | PYSEC-2025-184 |
| PyPI | pyspark | 3.4.4 | GHSA-6p6v-m64v-jx8q |
| PyPI | pyspark | 3.5.2 | GHSA-6p6v-m64v-jx8q |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Apache Software Foundation | Apache Spark | 3.5.0 – before 3.5.20 – before 3.4.4 |
| Apache Software Foundation | Apache Spark | 3.5.0 – before 3.5.20 – before 3.4.4 |
Weakness: CWE-347, CWE-326 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N