CVE-2026-44222 vLLM: Remote DoS via Special-Token Placeholders
Unauthenticated attackers can cause denial of service in vLLM by sending prompts with special token placeholders that trigger unhandled index errors.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-44222?
CVE-2026-44222 is a medium-severity denial of service vulnerability in Vllm Vllm, published on 12 May 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
vLLM is an inference and serving engine for large language models (LLMs). From 0.6.1 to before 0.20.0, there is a a Token Injection vulnerability in vLLM’s multimodal processing. Unauthenticated, text-only prompts that spell special tokens are interpreted as control. Image and video placeholder sequences supplied without matching data cause vLLM to index into empty grids during input-position computation, raising an unhandled IndexError and terminating the worker or degrading availability. Multimodal paths that rely on image_grid_thw/video_grid_thw are affected. This vulnerability is fixed in 0.20.0.
Weakness: CWE-129
Which versions are affected by CVE-2026-44222?
3 open source packages ship an affected version, including vllm. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
vllm PyPI | From 0.6.1 | 0.20.0 |
vllm PyPI | From 0.6.1 | 0.20.0 |
vllm PyPI | From 0.6.1 | 0.20.0 |
Products include Vllm Vllm.
How do I fix CVE-2026-44222?
Upgrade vllm to 0.20.0 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-44222 being exploited?
There is no known exploitation of CVE-2026-44222 in the wild and no public exploit code.
Other vulnerabilities in Vllm Vllm
- CVE-2025-32444 vLLM Vulnerable to Remote Code Execution via Mooncake Integration
- CVE-2026-22778 vLLM leaks a heap address when PIL throws an error
- CVE-2025-47277 vLLM Allows Remote Code Execution via PyNcclPipe Communication Service
- CVE-2024-11041 Remote Code Execution in vllm-project/vllm
- CVE-2026-48746 vLLM: OpenAI auth bypass
Sources
Also known as GHSA-hpv8-x276-m59f, MINI-p5m7-j6hc-r5g7, PYSEC-2026-3409.