LightLLM through 1.2.0 Unauthenticated Remote Code Execution via NCCL PD RPyC Control Channel

Advisories

LightLLM through 1.2.0 Unauthenticated Remote Code Execution via NCCL PD RPyC Control Channel

severity: critical
date: 9/23/2026
Affecting: LightLLM <= 1.2.0
CVE: CVE-2026-96560
CWE: CWE-502 Deserialization of Untrusted Data
CVSS: 9.3
CVSS V4 Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
References: GitHub Issue #1590
https://github.com/ModelTC/lightllm/blob/v1.2.0/lightllm/server/router/model_infer/mode_backend/pd/nccl_kv_transporter.py#L437-L461
https://github.com/ModelTC/lightllm/blob/v1.2.0/lightllm/server/router/model_infer/mode_backend/pd/nccl_kv_transporter.py#L411-L415
https://github.com/ModelTC/lightllm/blob/v1.2.0/lightllm/server/router/model_infer/mode_backend/pd/nccl_kv_transporter.py#L247-L249
https://github.com/ModelTC/lightllm/blob/v1.2.0/lightllm/server/router/model_infer/mode_backend/pd/kv_transporter.py#L20-L36
https://github.com/ModelTC/lightllm
Credit: Mingkai Yu, Jiapeng Li, Jiajia Liu
Description: LightLLM through 1.2.0 contains a remote code execution vulnerability in the KV-transfer worker when started with --pd_trans_mode nccl, which exposes an unauthenticated RPyC control channel that deserializes attacker-supplied data. Attackers can send malicious pickled objects to the exposed RPyC ThreadedServer to execute arbitrary code with the privileges of the LightLLM service account.

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