{"document":{"category":"csaf_vex","csaf_version":"2.0","title":"CVE-2026-41523: vLLM: Security Check Bypass via assert Statement in Activation Function Loading Allows Arbitrary Code Execution","publisher":{"category":"vendor","name":"HarborGuard Database","namespace":"https://database.harborguard.co"},"tracking":{"id":"CVE-2026-41523","status":"final","version":"1","initial_release_date":"2026-06-22T22:18:14.494Z","current_release_date":"2026-06-22T22:18:14.494Z","revision_history":[{"date":"2026-06-22T22:18:14.494Z","number":"1","summary":"Initial machine-readable export from HarborGuard."}]},"distribution":{"tlp":{"label":"WHITE"},"text":"Public CVE data; freely redistributable."},"notes":[{"category":"description","text":"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.","title":"CVE description"}],"references":[{"category":"self","summary":"CVE-2026-41523 on HarborGuard Database","url":"https://database.harborguard.co/cve/CVE-2026-41523"},{"category":"external","summary":"CVE Record","url":"https://www.cve.org/CVERecord?id=CVE-2026-41523"},{"category":"external","summary":"https://github.com/vllm-project/vllm/security/advisories/GHSA-q8gq-377p-jq3r","url":"https://github.com/vllm-project/vllm/security/advisories/GHSA-q8gq-377p-jq3r"},{"category":"external","summary":"https://github.com/vllm-project/vllm/commit/b3c7ffcab82c2439726f8cb213800f6f38c023d3","url":"https://github.com/vllm-project/vllm/commit/b3c7ffcab82c2439726f8cb213800f6f38c023d3"},{"category":"external","summary":"https://huntr.com/bounties/dcb05b04-e625-41e7-adbc-bbae0cc2d64c","url":"https://huntr.com/bounties/dcb05b04-e625-41e7-adbc-bbae0cc2d64c"}]},"product_tree":{"branches":[{"category":"vendor","name":"vllm-project","branches":[{"category":"product_name","name":"vllm","branches":[{"category":"product_version","name":"< 0.22.0","product":{"name":"vllm-project vllm < 0.22.0","product_id":"CSAFPID-1","product_identification_helper":{"cpe":"cpe:2.3:a:vllm-project:vllm:\\<_0.22.0:*:*:*:*:*:*:*"}}}]}]}]},"vulnerabilities":[{"cve":"CVE-2026-41523","title":"vLLM: Security Check Bypass via assert Statement in Activation Function Loading Allows Arbitrary Code Execution","notes":[{"category":"description","text":"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.","title":"CVE description"}],"product_status":{"known_affected":["CSAFPID-1"]},"scores":[{"cvss_v3":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H","baseScore":7.5,"baseSeverity":"HIGH"},"products":["CSAFPID-1"]}],"remediations":[{"category":"none_available","details":"No fixed version is published yet. Monitor the upstream advisory.","product_ids":["CSAFPID-1"]}]}]}