Bluewave Labs Checkmate up to 3.9.1 HTTP Monitor Matching monitorValidation.ts expectedValue incorrect bitwise shift of integer

Summaryinfo

A vulnerability was found in Bluewave Labs Checkmate up to 3.9.1. It has been declared as problematic. Affected is an unknown function of the file server/src/api/validation/monitorValidation.ts of the component HTTP Monitor Matching. Executing a manipulation of the argument expectedValue can lead to incorrect bitwise shift of integer. This vulnerability is tracked as CVE-2026-70656. The attack can be launched remotely. No exploit exists.

Detailsinfo

A vulnerability was found in Bluewave Labs Checkmate up to 3.9.1. It has been declared as problematic. This vulnerability affects some unknown processing of the file server/src/api/validation/monitorValidation.ts of the component HTTP Monitor Matching. The manipulation of the argument expectedValue with an unknown input leads to a incorrect bitwise shift of integer vulnerability. The CWE definition for the vulnerability is CWE-1335. An integer value is specified to be shifted by a negative amount or an amount greater than or equal to the number of bits contained in the value causing an unexpected or indeterminate result. As an impact it is known to affect availability. CVE summarizes:

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.

The advisory is available at github.com. This vulnerability was named CVE-2026-70656 since 08/04/2026. The exploitation appears to be easy. The attack can be initiated remotely. Additional levels of successful authentication are required for exploitation. Technical details are known, but there is no available exploit.

Upgrading to version 3.9.2 eliminates this vulnerability.

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Productinfo

Vendor

• Bluewave Labs

Name

• Checkmate

Version

• 3.9.0
• 3.9.1

CPE 2.3info

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CPE 2.2info

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