CVE-2026-70656

4.9 MEDIUM 0.6% exploit odds Fix listed Denial of service Server

What it is

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.

At a glance

Exploitability: Can be exploited over the network with an admin-level account. High risk of service disruption.
Exploit odds: 0.6% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2026-08-21 18:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-10-14 19:10 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.6% in the next 30 days (EPSS).
Severity: 4.9 MEDIUM (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2026-08-21 18:16 UTC
Last modified: 2026-10-14 19:10 UTC
Exploit probability: 0.6% · EPSS, next 30 days
Weakness: CWE-1333
Record status: Deferred

Attack profile CVSS 3.1 · 4.9

Attack vector: Network
Complexity: Low
Privileges needed: High
User interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

Raw vector

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

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-70656.md and follow it. Check whether this project is affected by CVE-2026-70656. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record