CVE-2026-41523
vLLM: Security Check Bypass via assert Statement in Activation Function Loading Allows Arbitrary Code Execution
CVSS Score
7.5
EPSS Score
0.5%
EPSS Percentile
39th
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.
| CWE | CWE-94 CWE-617 |
| Vendor | vllm-project |
| Product | vllm |
| Published | Jun 22, 2026 |
| Last Updated | Jul 22, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
Affected Versions
vllm-project / vllm
< 0.22.0
References
github.com: https://github.com/vllm-project/vllm/security/advisories/GHSA-q8gq-377p-jq3r github.com: https://github.com/vllm-project/vllm/commit/b3c7ffcab82c2439726f8cb213800f6f38c023d3 huntr.com: https://huntr.com/bounties/dcb05b04-e625-41e7-adbc-bbae0cc2d64c access.redhat.com: https://access.redhat.com/security/cve/CVE-2026-41523 bugzilla.redhat.com: https://bugzilla.redhat.com/show_bug.cgi?id=2491582 security.access.redhat.com: https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-41523.json access.redhat.com: https://access.redhat.com/errata/RHSA-2026:36005 access.redhat.com: https://access.redhat.com/errata/RHSA-2026:36006