---
cve: "CVE-2026-70656"
severity: "MEDIUM"
cvss: 4.9
epss: "6.8%"
vendor: "bluewave-labs"
kev: false
exploited: false
published: "2026-08-21 18:16:50"
tags: [cve, security, medium]
source: tsecurity.de CVE-Dossier
exported: "2026-09-04T07:21:21+02:00"
---

# CVE-2026-70656

> 4.9 MEDIUM · 🧪 PoC

## Beschreibung

Checkmate is an open-source, self-hosted tool designed to track and monitor server hardware, uptime, response times, and incidents in real-time with beautiful visualizations. From 3.5.1 until 3.9.2, an authenticated admin or superadmin can set matchMethod to regex and place a malicious expression in the expectedValue field for advanced HTTP monitor matching. server/src/api/validation/monitorValidation.ts accepts the expression, and server/src/service/network/AdvancedMatcher.ts synchronously evaluates it against an attacker-controlled HTTP response body on the Node.js main event loop without a timeout or worker isolation, allowing catastrophic backtracking to freeze API endpoints, monitor checks, and WebSocket connections for all users. This issue is fixed in version 3.9.2.

## CVSS-Vektor

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

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

## Patch verfügbar (OSV)

- 0df71d6356c87c747e0b796b0c34e33f2a5203fa (Commit)
- adba25269c455878bf8065bc28cfe5d74e58692f (Commit)

## Referenzen

- <https://github.com/bluewave-labs/Checkmate/security/advisories/GHSA-4c6j-p2cv-wf56>
- <https://github.com/bluewave-labs/Checkmate/commit/0df71d6356c87c747e0b796b0c34e33f2a5203fa>
- <https://github.com/bluewave-labs/Checkmate/commit/adba25269c455878bf8065bc28cfe5d74e58692f>
- <https://github.com/bluewave-labs/Checkmate/commit/d5ec2936ad77ab773529057b442a6eb55dd578eb>
- <https://github.com/bluewave-labs/Checkmate/releases/tag/v3.9.2>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-70656) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_