Vulnerability · Published Oct 5, 2026 · Assigned by GitHub_M
CVE-2026-105759vLLM: Unbounded Prometheus label cardinality from attacker-controlled HTTP method tokens in the vLLM Rust frontend metrics middleware (unauthenticated denial of service)
Medium 5.9
In plain English
A medium-severity uncontrolled resource consumption in vllm from vllm-project. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 36% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| PyPI | vllm | 0.30.0 | PYSEC-2026-4325 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| vllm-project | vllm | < 0.30.0 |
Weakness: CWE-400 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
References
- https://github.com/vllm-project/vllm/security/advisories/GHSA-5fj9-pfhr-6j48 x_refsource_CONFIRM
- https://github.com/vllm-project/vllm/pull/56058 x_refsource_MISC
- https://github.com/vllm-project/vllm/commit/3735c2d5f5248259482b9045c34fb7a8a3892352 x_refsource_MISC
- https://github.com/vllm-project/vllm/releases/tag/v0.30.0 x_refsource_MISC