{"id":"CVE-2026-55241","summary":"Checkmate: Pre-auth Denial of Service via File Upload on Registration","details":"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.","aliases":["GHSA-9xvg-x28f-m78m"],"modified":"2026-09-20T11:30:38.879294832Z","published":"2026-08-21T17:57:10.014Z","database_specific":{"cna_assigner":"GitHub_M","cwe_ids":["CWE-400","CWE-770"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55241.json"},"references":[{"type":"WEB","url":"https://github.com/bluewave-labs/Checkmate/releases/tag/v3.9.1"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55241.json"},{"type":"ADVISORY","url":"https://github.com/bluewave-labs/Checkmate/security/advisories/GHSA-9xvg-x28f-m78m"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-55241"},{"type":"FIX","url":"https://github.com/bluewave-labs/Checkmate/commit/091c36cbf338b673110b0806d76df26d52516468"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/bluewave-labs/checkmate","events":[{"introduced":"0"},{"fixed":"091c36cbf338b673110b0806d76df26d52516468"},{"fixed":"825bcc5fdbd0dbde9e78033ce844ab880a46083a"}],"database_specific":{"extracted_events":[{"introduced":"0"},{"fixed":"3.9.1"}],"source":["AFFECTED_FIELD","REFERENCES"]}}],"versions":["v3.8.1","v3.8.0","untagged-819f0fe0d99d8d0b5f14","v3.7.1","v3.6.1","v3.5.1","v3.5.0","v3.4.0","v3.3","v3.2.0","v3.1.8","v3.1.7","v3.1.6","v3.1.5","v3.1.4","v3.1.3","v3.1.2","v3.1.1","v3.1","v3.1-beta","V3.0-beta","v2.3.1","v2.3","v2.2","v2.1.1","v2.1","v2.0.2","v2.0.1","v1.1.0","v1.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-55241.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"}]}