---
id: CVE-2026-76850
title: LMDeploy deserializes disaggregated-serving peer messages with pickle
summary: >-
  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…
severity: critical
cvss: 9.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-502
vendor: InternLM
product: lmdeploy
affected:
  - lmdeploy >= 0.9.2 < 0.16.0
published: '2026-08-19'
updated: '2026-09-24'
sourceUpdated: '2026-09-24T20:06:30.133'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-76850'
references:
  - url: 'https://github.com/InternLM/lmdeploy'
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/InternLM/lmdeploy/blob/v0.15.0/lmdeploy/pytorch/disagg/conn/engine_conn.py#L61
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/InternLM/lmdeploy/blob/v0.15.0/lmdeploy/pytorch/disagg/conn/engine_conn.py#L79
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/InternLM/lmdeploy/commit/f05b4ad8bf2e2d84101a1d63b3c44fadd99223b2
    label: disclosure@vulncheck.com
  - url: 'https://github.com/InternLM/lmdeploy/issues/4804'
    label: disclosure@vulncheck.com
  - url: 'https://github.com/InternLM/lmdeploy/releases/tag/v0.16.0'
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/lmdeploy-remote-code-execution-via-unsafe-pickle-deserialization-in-the-disaggregated-serving-peer-connector
    label: disclosure@vulncheck.com
  - url: 'https://github.com/InternLM/lmdeploy/issues/4804'
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
tags:
  - nvd
  - cve.org
  - exploit-available
epss: 0.01271
epssPercentile: 0.69695
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'yes'
  technicalImpact: total
  timestamp: '2026-08-20T14:08:23.395015Z'
ingestedAt: '2026-09-24T15:45:56.699Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.