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
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2025-55039 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 378,156 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
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' |
Detection & 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.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2025-55039 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2025-55039. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2025-55039 in your dependencies?
O3 Security finds CVE-2025-55039 across Maven, PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.