---
id: CVE-2026-103042
title: >-
  LightLLM through 1.2.0 contains a memory exhaustion vulnerability in the NCCL
  control channel when started with --pd_trans_mode nccl, allowing
  unauthenticated attackers to exhaust KV-transfer worker memory
summary: >-
  LightLLM through 1.2.0 contains a memory exhaustion vulnerability in the NCCL
  control channel when started with --pd_trans_mode nccl, allowing
  unauthenticated attackers to exhaust KV-transfer worker memory. Attackers can
  call the exposed…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-770
vendor: ModelTC
product: LightLLM
affected:
  - LightLLM <= 1.2.0
published: '2026-09-29'
updated: '2026-10-02'
sourceUpdated: '2026-10-02T13:17:36.763'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-103042'
references:
  - url: 'https://github.com/ModelTC/LightLLM'
    label: disclosure@vulncheck.com
  - url: 'https://github.com/ModelTC/LightLLM/issues/1595'
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/ModelTC/lightllm/blob/v1.2.0/lightllm/server/router/model_infer/mode_backend/pd/base_kv_move_manager.py#L121-L122
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/ModelTC/lightllm/blob/v1.2.0/lightllm/server/router/model_infer/mode_backend/pd/nccl_kv_transporter.py#L416-L420
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/ModelTC/lightllm/blob/v1.2.0/lightllm/server/router/model_infer/mode_backend/pd/nccl_kv_transporter.py#L474-L485
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/lightllm-through-1.2.0-unauthenticated-memory-exhaustion-via-nccl-control-channel-set-value
    label: disclosure@vulncheck.com
  - url: 'https://github.com/ModelTC/LightLLM/issues/1595'
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
tags:
  - nvd
  - cve.org
  - exploit-available
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-10-02T12:31:46.084047Z'
epss: 0.00646
epssPercentile: 0.50741
ingestedAt: '2026-09-29T23:52:50.535Z'
---

## Overview

LightLLM through 1.2.0 contains a memory exhaustion vulnerability in the NCCL control channel when started with --pd_trans_mode nccl, allowing unauthenticated attackers to exhaust KV-transfer worker memory. Attackers can call the exposed_set_value method to store unbounded key-value pairs without size limits, causing the worker process to crash and triggering node failure.

## Remediation

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