CVE-2026-76850

Critical · CVSS 9.3

Published 2026-08-19

CVSS

9.3

Critical

EPSS

—

exploit probability

Active Exploit

not yet listed

High — patch soon — High severity. Target patch within 7 days.

What is CVE-2026-76850?

LMDeploy deserializes disaggregated-serving peer messages with pickle. The handle_zmq_recv coroutine in lmdeploy/pytorch/disagg/conn/engine_conn.py reads peer-to-peer cache-free requests with recv_pyobj(), which deserializes the received bytes with pickle.loads(), and the isinstance check against DistServeCacheFreeRequest runs only after deserialization has already completed. The peer that supplies those bytes is caller-controlled: p2p_connect passes remote_engine_endpoint_info.zmq_address from the request body to connect() on the ZMQ PULL socket, and the POST /distserve/p2p_initialize and /distserve/p2p_connect endpoints in lmdeploy/serve/openai/api_server.py apply no authentication unless the server is started with api_keys, which defaults to None. A remote attacker can direct an engine to pull from a ZMQ endpoint under their control and execute arbitrary code in the engine process. Deployments that do not enable disaggregated serving are not affected, because the receive loop is only started once the migration backend accepts the connection.

CVSS Score Explained

CVSS 9.3 is Critical — the highest severity tier. Attackers can likely exploit this remotely with no authentication and cause full system compromise. Patch immediately.

EPSS Exploitation Probability

No EPSS score yet — model needs more data on this CVE.

References & Patches

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