CVE-2025-55039 is a medium-severity (CVSS 6.5) CWE-326 vulnerability in org.apache.spark:spark-network-common_2.13. A fix is available for org.apache.spark:spark-network-common_2.13 — see the affected versions and patch details below.
Apache Spark, Apache Spark: RPC encryption defaults to unauthenticated AES-CTR mode, enabling man-in-the-middle ciphertext modification attacks
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2025-55039.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
org.apache.spark:spark-network-common_2.13☕org.apache.spark:spark-network-common_2.13☕org.apache.spark:spark-network-common_2.12☕org.apache.spark:spark-network-common_2.12🐍pyspark🐍pysparkReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.
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
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.apache.spark:spark-network-common_2.13 | ≥ 3.5.0&&< 3.5.2 | 3.5.2org.apache.spark:spark-network-common_2.13:3.5.2 |
| ☕Maven | org.apache.spark:spark-network-common_2.13 | all versions | 3.4.4org.apache.spark:spark-network-common_2.13:3.4.4 |
| ☕Maven | org.apache.spark:spark-network-common_2.12 | all versions | 3.4.4org.apache.spark:spark-network-common_2.12:3.4.4 |
| ☕Maven | org.apache.spark:spark-network-common_2.12 | ≥ 3.5.0&&< 3.5.2 | 3.5.2org.apache.spark:spark-network-common_2.12:3.5.2 |
| 🐍PyPI | pyspark | all versions | 3.4.4pip install --upgrade 'pyspark==3.4.4' |
| 🐍PyPI | pyspark | ≥ 3.5.0&&< 3.5.2 | 3.5.2pip install --upgrade 'pyspark==3.5.2' |
Affected Products
sparkapacheDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.apache.spark:spark-network-common_2.13, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.apache.spark:spark-network-common_2.13 to 3.5.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-55039 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
Frequently Asked Questions
Is CVE-2025-55039 in your dependencies?
Find it across Maven, PyPI, including transitive dependencies.