CVE-2026-44222: vLLM: Remote DoS via Special-Token Placeholders

Vulnerability summary

CVE-2026-44222 is a high (CVSS 7.5) Improper Validation of Array Index vulnerability in vllm-project vllm. EPSS estimates a 0.46% chance of exploitation in the next 30 days, higher than 38.4% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 12-05-2026
   PublishedVulnerability first disclosed.
2. 13-05-2026
   Last modifiedVulnerability information updated.

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.

• CWE-129Improper Validation of Array IndexThe product uses untrusted input when calculating or using an array index, but the product does not validate or incorrectly validates the index to ensure the index references a valid position within the array.