Which versions of LightLLM are affected by CVE-2026-26220?

LightLLM versions 1.1.0 and prior contain a critical remote code execution vulnerability affecting organizations using prefill-decode disaggregation mode, allowing unauthenticated attackers to gain…

How to fix or mitigate CVE-2026-26220?

Within 24 hours, identify and audit all LightLLM deployments running version 1.1.0 or prior, particularly those in prefill-decode mode, and assess their network exposure. Within 7 days, implement network segmentation to restrict WebSocket access to LightLLM master nodes, disable prefill-decode disaggregation mode if operationally feasible, and establish detailed logging of WebSocket endpoint access. Within 30 days, develop a migration plan to transition to an alternative LLM serving framework or upgrade if a vendor patch becomes available; maintain network isolation and continuous monitoring as controls until resolution.

LightLLM CVE-2026-26220

Q: What is the CVSS score of CVE-2026-26220?

CVE-2026-26220 has a CVSS 4.0 base score of 9.3 (Critical). CVSS 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. EPSS exploitation probability: 0.8%.

CRITICAL

Deserialization of Untrusted Data (CWE-502)

2026-02-17 disclosure@vulncheck.com

RCE Deserialization

9.3

CVSS 4.0 · Vendor: vulncheck

Severity by source

Vendor (vulncheck) PRIMARY

9.3 CRITICAL

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Primary rating from Vendor (vulncheck) · only source for this CVE.

CVSS VectorVendor: vulncheck

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Lifecycle Timeline

Analysis Updated

Jul 14, 2026 - 16:32 vuln.today

v2 (cvss_changed)

Re-analysis Queued

Jul 14, 2026 - 16:22 vuln.today

cvss_changed

CVSS changed

Jul 14, 2026 - 16:22 NVD

9.3 (CRITICAL)

Analysis Generated

Mar 12, 2026 - 21:55 vuln.today

CVE Published

Feb 17, 2026 - 03:16 nvd

N/A

DescriptionCVE.org

LightLLM version 1.1.0 and prior contain an unauthenticated remote code execution vulnerability in PD (prefill-decode) disaggregation mode. The PD master node exposes WebSocket endpoints that receive binary frames and pass the data directly to pickle.loads() without authentication or validation. A remote attacker who can reach the PD master can send a crafted payload to achieve arbitrary code execution.

AnalysisAI

Remote code execution in LightLLM 1.1.0 and prior lets unauthenticated attackers run arbitrary code on the PD master node when the framework runs in prefill-decode (PD) disaggregation mode. The PD master exposes WebSocket endpoints that feed inbound binary frames straight into Python's pickle.loads(), so any attacker able to reach that socket can execute code in the serving process. No CISA KEV listing exists and EPSS is modest at 0.83% (74th percentile), but a public technical write-up (chocapikk.com) plus a VulnCheck advisory mean publicly available exploit code exists, so this should be treated as an urgent internal-exposure risk.