---
cve: "CVE-2026-73556"
severity: "MEDIUM"
cvss: 5.3
epss: "32%"
vendor: "vllm-project"
kev: false
exploited: false
published: "2026-08-13 15:20:17"
tags: [cve, security, medium]
source: tsecurity.de CVE-Dossier
exported: "2026-09-17T05:02:56+02:00"
---

# CVE-2026-73556

> 5.3 MEDIUM · 🧪 PoC

## Beschreibung

vLLM is an inference and serving engine for large language models. Prior to 0.26.0, the structured_outputs.regex parameter in vllm/v1/structured_output/backend_lm_format_enforcer.py is passed to lmformatenforcer.RegexParser without compile_regex_with_timeout or validation in validate_structured_output_request_lm_format_enforcer, allowing an unauthenticated /v1/completions request against the lm-format-enforcer backend to consume a CPU core and stall the structured-output engine path with a catastrophic regular expression. This issue is fixed in version 0.26.0.

## CVSS-Vektor

```
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |
| S Scope | Unverändert | good |
| C Vertraulichkeit | Keine | good |
| I Integrität | Keine | good |
| A Verfügbarkeit | Gering | warn |

## Patch verfügbar (OSV)

- c9a788eedc412acceaa5112e0d44624b49841577 (Commit)
- ffd46bfab2128bb84146050e98b51a617c6575ab (Commit)

## Referenzen

- <https://github.com/vllm-project/vllm/security/advisories/GHSA-48jh-3gj7-fg8v>
- <https://github.com/vllm-project/vllm/pull/47595>
- <https://github.com/vllm-project/vllm/commit/c9a788eedc412acceaa5112e0d44624b49841577>
- <https://github.com/vllm-project/vllm/releases/tag/v0.26.0>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-73556) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_