What’s Vulnerable › Vulnerabilities

CVE-2026-55241: Checkmate: Pre-auth Denial of Service via File Upload on Registration

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-21 · updated 2026-10-14
• Weakness: CWE-400

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.

Affected products

• bluewave-labs Checkmate: before 3.9.1

References

• https://github.com/bluewave-labs/Checkmate/commit/091c36cbf338b673110b0806d76df26d52516468
• https://github.com/bluewave-labs/Checkmate/releases/tag/v3.9.1
• https://github.com/bluewave-labs/Checkmate/security/advisories/GHSA-9xvg-x28f-m78m
• https://github.com/bluewave-labs/Checkmate/security/advisories/GHSA-9xvg-x28f-m78m

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