High [CVE-2026-41523] Arbitrary code execution via malicious HuggingFace model

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.

Red Hat rates this issue as having Important impact for Red Hat AI Inference Server and Red Hat OpenShift AI vLLM serving images, and Moderate impact for Red Hat Enterprise Linux AI bootc images that bundle vLLM. Red Hat AI Inference Server 3.2/3.3 images and other components without the vulnerable pooler activation loader (vLLM < 0.14.0) are not affected.

Red Hat severity: Important — CVSS 7.5 (CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H). Weakness: CWE-617.

Affected Red Hat products: Red Hat AI Inference Server 3.2; Red Hat AI Inference Server 3.3; Red Hat AI Inference Server 3.4; Red Hat Enterprise Linux AI 3.3; Red Hat Enterprise Linux AI 3.4; Red Hat AI Inference Server; Red Hat OpenShift AI (RHOAI). Will not fix / out of support: Red Hat AI Inference Server.