How severe is CVE-2026-31234?

CVE-2026-31234 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-31234 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (48th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-31234?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

Does CVE-2026-31234 have an EU (EUVD) identifier?

Yes. CVE-2026-31234 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-29557.

When was CVE-2026-31234 published?

CVE-2026-31234 was published on 2026-05-12 and last updated on 2026-06-17.

CVE-2026-31234

CVE-2026-31234 is a critical-severity vulnerability with a CVSS 3.x base score of 9.8. 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-502.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
EPSS exploit prediction: 1% (48th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-29557
Weakness: CWE-502
Published: 2026-05-12
Last modified: 2026-06-17

Description

Horovod thru 0.28.1 contains an insecure deserialization vulnerability (CWE-502) in its KVStore HTTP server component. The KVStore server, used for distributed task coordination, lacks authentication and authorization controls, allowing any remote attacker to write arbitrary data via HTTP PUT requests. When a Horovod worker reads data from the KVStore (via HTTP GET), it deserializes the data using cloudpickle.loads() without verifying its source or integrity. An attacker can exploit this by sending a malicious pickle payload to the server before the legitimate data is written, causing the victim worker to deserialize and execute arbitrary code, leading to remote code execution.

Frequently asked questions

What is CVE-2026-31234?: Horovod thru 0.28.1 contains an insecure deserialization vulnerability (CWE-502) in its KVStore HTTP server component. The KVStore server, used for distributed task coordination, lacks authentication and authorization controls, allowing any remote attacker to write arbitrary data via HTTP PUT requests. When a Horovod worker reads data from the KVStore (via HTTP GET), it deserializes the data using cloudpickle.loads() without verifying its source or integrity. An attacker can exploit this by sending a malicious pickle payload to the server before the legitimate data is written, causing the victim worker to deserialize and execute arbitrary code, leading to remote code execution.
How severe is CVE-2026-31234?: CVE-2026-31234 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-31234 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (48th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-31234?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2026-31234 have an EU (EUVD) identifier?: Yes. CVE-2026-31234 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-29557.
When was CVE-2026-31234 published?: CVE-2026-31234 was published on 2026-05-12 and last updated on 2026-06-17.

References

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