How severe is CVE-2025-55039?

CVE-2025-55039 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2025-55039 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (13th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-55039?

CVE-2025-55039 affects Apache Spark. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2025-55039?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2025-55039 have an EU (EUVD) identifier?

Yes. CVE-2025-55039 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-34531.

When was CVE-2025-55039 published?

CVE-2025-55039 was published on 2025-10-15 and last updated on 2026-06-17.

CVE-2025-55039

CVE-2025-55039 is a medium-severity vulnerability in Apache Spark with a CVSS 3.x base score of 6.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-326.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
EPSS exploit prediction: 0% (13th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-34531
Weakness: CWE-326
Affected product: Apache Spark
Published: 2025-10-15
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2025-55039?: 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.
How severe is CVE-2025-55039?: CVE-2025-55039 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2025-55039 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (13th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-55039?: CVE-2025-55039 affects Apache Spark. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-55039?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2025-55039 have an EU (EUVD) identifier?: Yes. CVE-2025-55039 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-34531.
When was CVE-2025-55039 published?: CVE-2025-55039 was published on 2025-10-15 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:apache:spark:*:*:*:*:*:*:*:*

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