Vulnerability · Published Aug 19, 2026 · Assigned by VulnCheck
CVE-2026-76850LMDeploy Remote Code Execution via Unsafe Pickle Deserialization in the Disaggregated Serving Peer Connector
Critical 9.8
In plain English
A critical-severity unsafe deserialization in lmdeploy from InternLM. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 1.3% (higher than 70% of all known vulnerabilities).
Official description
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.
Affected products (as reported)
Weakness: CWE-502 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
References
- GitHub Issue #4804 issue-tracking
- fix(disagg): use JSON instead of pickle for P2P ZMQ requests patch
- Vulnerable recv_pyobj() call in v0.15.0 technical-description
- Caller-controlled zmq_address passed to connect() in v0.15.0 technical-description
- lmdeploy v0.16.0 Release Notes release-notes
- https://github.com/InternLM/lmdeploy product
- VulnCheck Advisory: LMDeploy Remote Code Execution via Unsafe Pickle Deserialization in the Disaggregated Serving Peer Connector third-party-advisory