---
id: CVE-2026-55241
title: >-
  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
summary: >-
  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…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-400
  - CWE-770
published: '2026-08-21'
updated: '2026-09-18'
sourceUpdated: '2026-09-18T20:09:01.757'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-55241'
references:
  - url: >-
      https://github.com/bluewave-labs/Checkmate/commit/091c36cbf338b673110b0806d76df26d52516468
    label: security-advisories@github.com
  - url: 'https://github.com/bluewave-labs/Checkmate/releases/tag/v3.9.1'
    label: security-advisories@github.com
  - url: >-
      https://github.com/bluewave-labs/Checkmate/security/advisories/GHSA-9xvg-x28f-m78m
    label: security-advisories@github.com
  - url: >-
      https://github.com/bluewave-labs/Checkmate/security/advisories/GHSA-9xvg-x28f-m78m
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
tags:
  - nvd
epss: 0.00618
epssPercentile: 0.47316
ingestedAt: '2026-09-18T20:51:25.655Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.