CVE-2026-70656
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.
Scoring
- Severity
- MEDIUM
- CVSS base score
- 4.9
- CVSS vector
- CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
- EPSS probability
- 0.42%
- CWE
- CWE-1333
- Published
- 2026-08-21
- Last modified
- 2026-08-21
Affected products
- bluewave-labs Checkmate
Weakness type
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