SEPTEMBER 18, 2026
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Case File

CVE-2026-70656

MEDIUM · CVSS 4.9 EPSS 0.42% Public Exploit

Source: NVD + CISA KEV + EPSS · Published 2026-08-21 · Last synced 2026-09-18

CyberRota Analysis

AI-Generated

Authenticated admin or superadmin users of Checkmate versions 3.5.1 to 3.9.2 are vulnerable to a denial-of-service attack due to improper handling of regular expressions in the HTTP monitor matching feature. An attacker can exploit this vulnerability by injecting a malicious regex into the expectedValue field, leading to catastrophic backtracking that can freeze API endpoints and disrupt service for all users. Organizations using affected versions should prioritize upgrading to version 3.9.2 to mitigate this risk.

Public Exploit Signal

A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.

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CVE
CVE-2026-70656
Severity
MEDIUM
CVSS
4.9
EPSS
0.42%

Original NVD Description

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.