CVE-2026-76850 LMDeploy Remote Code Execution via Unsafe Pickle Deserialization in the Disaggregated Serving Peer Connector
Remote attackers can execute arbitrary code in LMDeploy engines by sending malicious pickle data to unauthenticated peer connectors when disaggregated serving is enabled.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-76850?
CVE-2026-76850 is a critical unsafe deserialization vulnerability in InternLM lmdeploy, published on 19 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
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.
Weakness: CWE-502
Which versions are affected by CVE-2026-76850?
How do I fix CVE-2026-76850?
No fix has been published for CVE-2026-76850 yet. Limit exposure of the affected software until one is available.
Upgrade, and only deserialise data from trusted sources or with an allow-list of types. More about Unsafe deserialization.
Is CVE-2026-76850 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-76850 exists.
Sources
Also known as GHSA-q66m-3fcg-jjh7.