Horovod up to 0.28.1 Pickle cloudpickle.loads deserialization

Summaryinfo

A vulnerability has been found in Horovod up to 0.28.1 and classified as critical. Impacted is the function cloudpickle.loads of the component Pickle Handler. This manipulation causes deserialization. This vulnerability is tracked as CVE-2026-31234. The attack is possible to be carried out remotely. No exploit exists.

Detailsinfo

A vulnerability was found in Horovod up to 0.28.1. It has been declared as critical. Affected by this vulnerability is the function cloudpickle.loads of the component Pickle Handler. The manipulation with an unknown input leads to a deserialization vulnerability. The CWE definition for the vulnerability is CWE-502. The product deserializes untrusted data without sufficiently verifying that the resulting data will be valid. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

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.

This vulnerability is known as CVE-2026-31234 since 03/09/2026. The exploitation appears to be easy. The attack can be launched remotely. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 05/12/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Name

• Horovod

Version

• 0.28.0
• 0.28.1

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CPE 2.2info

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