CVE-2026-105759

vLLM: Unbounded Prometheus label cardinality from attacker-controlled HTTP method tokens in the vLLM Rust frontend metrics middleware (unauthenticated denial of service)

State
Published
Severity
5.9 Medium
Published
Oct 5, 2026
Updated
Oct 6, 2026
Reserved
Oct 5, 2026

Read the record on cve.org

Description

vLLM is an inference and serving engine for large language models. Prior to 0.30.0, the Rust frontend's track_http_metrics middleware records the raw HTTP method token as a Prometheus label for requests reaching registered routes. An unauthenticated attacker can send unique arbitrary method tokens to unguarded routes such as /tokenize, causing Prometheus's Family::get_or_create function to permanently create counter and histogram label sets. Those label sets increase process memory usage and enlarge the /metrics response until the service or monitoring path is exhausted. This issue is fixed in version 0.30.0.

Scores

CVSSScoreVectorSource
3.15.9 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:HGitHub_M

Weaknesses

  • CWE-400 Uncontrolled Resource Consumption

Affected Products

ProductVersions
vllmvllm-project
  • < 0.30.0Affected

References

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