Unauthenticated code execution via poisoned KVStore deserialization
Published May 12, 2026 · Updated May 12, 2026
Insecure deserialization in Horovod 0.28.1 and earlier allows remote attackers to execute arbitrary code through the KVStore HTTP server. The server accepts unauthenticated HTTP PUT data, and a worker later passes the retrieved bytes to cloudpickle.loads() without verifying their origin or integrity. Exploitation requires network access and winning the write-before-legitimate-data race, after which the payload runs with the worker process privileges.
Summary
What happened
Insecure deserialization in Horovod 0.28.1 and earlier allows remote attackers to execute arbitrary code through the KVStore HTTP server. The server accepts unauthenticated HTTP PUT data, and a worker later passes the retrieved bytes to cloudpickle.loads() without verifying their origin or integrity. Exploitation requires network access and winning the write-before-legitimate-data race, after which the payload runs with the worker process privileges.
The record
- CVE
- CVE-2026-31234
- Published
- May 12, 2026
- Updated
- May 12, 2026
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-502, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- May 12, 2026CVE publishedPublication date reported by the CVE source.
- May 12, 2026Record updatedLatest update available in the CVE record.
Exploitability
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Attacks
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