CVE-2026-70656: CWE-1333: Inefficient Regular Expression Complexity in bluewave-labs Checkmate
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.
AI Analysis
Technical Summary
Checkmate, an open-source server monitoring tool, contains a vulnerability in versions >=3.5.1 and <3.9.2 where an authenticated admin or superadmin can set the matchMethod to regex and supply a malicious regular expression in the expectedValue field. The server synchronously evaluates this regex against attacker-controlled HTTP response bodies on the Node.js main event loop without timeout or worker isolation. This allows catastrophic backtracking, resulting in denial of service by freezing API endpoints, monitor checks, and WebSocket connections for all users. The vulnerability is identified as CWE-1333 (Inefficient Regular Expression Complexity) and is fixed in version 3.9.2.
Potential Impact
Exploitation requires authenticated admin or superadmin privileges. The vulnerability does not impact confidentiality or integrity but causes a denial of service by freezing critical server components, disrupting monitoring and API functionality for all users.
Mitigation Recommendations
Upgrade Checkmate to version 3.9.2 or later, where this vulnerability is fixed. No other official remediation or temporary workaround is documented. Patch status is not explicitly stated but the fix is included in version 3.9.2.
CVE-2026-70656: CWE-1333: Inefficient Regular Expression Complexity in bluewave-labs Checkmate
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.
CVSS v3.1
Score 4.9medium
Affected software
pkg:github/bluewave-labs/CheckmateRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
Checkmate, an open-source server monitoring tool, contains a vulnerability in versions >=3.5.1 and <3.9.2 where an authenticated admin or superadmin can set the matchMethod to regex and supply a malicious regular expression in the expectedValue field. The server synchronously evaluates this regex against attacker-controlled HTTP response bodies on the Node.js main event loop without timeout or worker isolation. This allows catastrophic backtracking, resulting in denial of service by freezing API endpoints, monitor checks, and WebSocket connections for all users. The vulnerability is identified as CWE-1333 (Inefficient Regular Expression Complexity) and is fixed in version 3.9.2.
Potential Impact
Exploitation requires authenticated admin or superadmin privileges. The vulnerability does not impact confidentiality or integrity but causes a denial of service by freezing critical server components, disrupting monitoring and API functionality for all users.
Mitigation Recommendations
Upgrade Checkmate to version 3.9.2 or later, where this vulnerability is fixed. No other official remediation or temporary workaround is documented. Patch status is not explicitly stated but the fix is included in version 3.9.2.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-08-04T21:48:08.612Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a8893f9acd9273b4983fd4e
Added to database: 08/21/2026, 18:07:53 UTC
Last enriched: 08/21/2026, 18:22:30 UTC
Last updated: 08/21/2026, 22:44:44 UTC
Views: 9
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