CVE-2026-41523
HIGH 7.5vLLM 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.
Severe if exploited (CVSS 7.5), but no known exploitation and low modeled probability. Patch on a normal cadence.
Exploitation likelihood
0.5%chance of exploitation in 30 days · 37th percentile
Impact if exploited
7.5CVSS 3.1 · HIGH
- ConfidentialityHigh
- IntegrityHigh
- AvailabilityHigh
What an attacker needs
- ✓Access: Reachable over the network — no local access needed
- ✓Privileges: No account or privileges required
- ⚠User interaction: A user must take an action (click / open a file)
- ⚠Complexity: Needs a race window or specific setup
✓ lowers the bar for an attacker · ⚠ raises it
Affected
Vendors Vllm Project Red Hat
Products Vllm Red Hat Ai Inference Server Red Hat Enterprise Linux Ai (Rhel Ai) 3 Red Hat Openshift Ai (Rhoai)
Weakness (CWE)
- CWE-94: Code injection
- CWE-617
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
References
Technical & other
- https://github.com/vllm-project/vllm/security/advisories/GHSA-q8gq-377p-jq3r
- https://github.com/vllm-project/vllm/commit/b3c7ffcab82c2439726f8cb213800f6f38c023d3
- https://huntr.com/bounties/dcb05b04-e625-41e7-adbc-bbae0cc2d64c
- https://access.redhat.com/security/cve/CVE-2026-41523
- https://bugzilla.redhat.com/show_bug.cgi?id=2491582
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-41523.json