AIKIDO-2026-631276
vllm is vulnerable to Regular Expression Denial of Service (ReDoS)
53
Medium Risk
This Affects:
vllmTL;DR
The lm-format-enforcer structured-output backend compiles a user-supplied regular expression into a finite-state machine without a compile timeout or buildability check. A single request containing a catastrophic pattern pegs a CPU core during grammar compilation and stalls the structured-output engine path. This blocks concurrent requests and causes denial of service. The fix routes the compile through the same timeout guard already applied to the other structured-output backends.
Who does this affect?
You are affected if you are using a version that falls within the vulnerable range and you have selected the lm-format-enforcer structured outputs backend and accept user-controlled regular expressions.
Background info
vllm is vulnerable to Regular Expression Denial of Service (ReDoS) in versions 0.10.2 - 0.25.1.
How to fix this
Upgrade the vllm library to the patch version.
Are You Affected?
Connect your repositories to instantly see whether vulnerable or malicious packages exist in your codebase.
Free. No credit card required.
I consent to receiving marketing communications based on Aikido’s Privacy Policy.
SOC 2Compliant
ISO 27001Compliant