CVE-2026-41523: vLLM: Security Check Bypass via assert Statement in Activation Function Loading Allows Arbitrary Code Execution
(updated )
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).
References
- access.redhat.com/errata/RHSA-2026:36005
- access.redhat.com/errata/RHSA-2026:36006
- access.redhat.com/security/cve/CVE-2026-41523
- bugzilla.redhat.com/show_bug.cgi?id=2491582
- github.com/advisories/GHSA-q8gq-377p-jq3r
- github.com/pypa/advisory-database/tree/main/vulns/vllm/PYSEC-2026-2300.yaml
- github.com/vllm-project/vllm/commit/b3c7ffcab82c2439726f8cb213800f6f38c023d3
- github.com/vllm-project/vllm/security/advisories/GHSA-q8gq-377p-jq3r
- huntr.com/bounties/dcb05b04-e625-41e7-adbc-bbae0cc2d64c
- nvd.nist.gov/vuln/detail/CVE-2026-41523
- security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-41523.json
Code Behaviors & Features
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