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. Prior to 3.9.1, the public POST /api/v1/auth/register route in server/src/api/routes/authRoutes.ts passes multipart profileImage uploads through in-memory Multer parsing before registration validation, without file-size, file-count, or MIME-type limits in server/src/api/middleware/upload.ts. An unauthenticated attacker can submit concurrent oversized files that are buffered before invalid registration or invite-token checks reject the request, exhausting memory and crashing or destabilizing the backend. This issue is fixed in version 3.9.1.
Advisories

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Fixes

Solution

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Workaround

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History

Fri, 21 Aug 2026 19:45:00 +0000

Type Values Removed Values Added
First Time appeared Bluewave-labs
Bluewave-labs checkmate
Vendors & Products Bluewave-labs
Bluewave-labs checkmate

Fri, 21 Aug 2026 18:15:00 +0000

Type Values Removed Values Added
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. Prior to 3.9.1, the public POST /api/v1/auth/register route in server/src/api/routes/authRoutes.ts passes multipart profileImage uploads through in-memory Multer parsing before registration validation, without file-size, file-count, or MIME-type limits in server/src/api/middleware/upload.ts. An unauthenticated attacker can submit concurrent oversized files that are buffered before invalid registration or invite-token checks reject the request, exhausting memory and crashing or destabilizing the backend. This issue is fixed in version 3.9.1.
Title Checkmate: Pre-auth Denial of Service via File Upload on Registration
Weaknesses CWE-400
CWE-770
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-08-21T17:57:10.014Z

Reserved: 2026-06-16T16:44:00.624Z

Link: CVE-2026-55241

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-08-21T18:16:48.790

Modified: 2026-08-21T18:16:48.790

Link: CVE-2026-55241

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-08-21T19:45:03Z

Weaknesses