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CVE-2026-41523

vLLM: Security Check Bypass via assert Statement in Activation Function Loading Allows Arbitrary Code Execution PUBLISHED

Description (CNA)

vLLM is an inference and serving engine for large language models (LLMs). Prior to 0.22.0, an assert-based security check in vLLM's activation function loading allows any unauthenticated attacker to achieve arbitrary code execution on the server by publishing a malicious HuggingFace model, when vLLM runs in Python optimized mode (python -O or PYTHONOPTIMIZE=1). This vulnerability is fixed in 0.22.0.

Affected (CNA)

Vendor / productVersions
vllm-project / vllmaffected < 0.22.0

CWE

CWE-94, CWE-617

References

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.

redhat-SADP

A flaw was found in vLLM, an inference and serving engine for large language models (LLMs). An unauthenticated attacker can exploit an assert-based security check during activation function loading. By publishing a malicious HuggingFace model, an attacker can achieve arbitrary code execution on the server when vLLM runs in Python optimized mode.