{"id":"CVE-2026-55241","state":"PUBLISHED","title":"Checkmate: Pre-auth Denial of Service via File Upload on Registration","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.","publishedAt":"2026-08-21T17:57:10.014Z","updatedAt":"2026-08-25T11:51:15.776Z","severity":{"score":7.5,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","source":"GitHub_M"},"assigner":"GitHub_M","products":["bluewave-labs Checkmate"],"affected":[{"vendor":"bluewave-labs","product":"Checkmate","versions":[{"version":"< 3.9.1","status":"affected"}]}],"references":["https://github.com/bluewave-labs/Checkmate/security/advisories/GHSA-9xvg-x28f-m78m","https://github.com/bluewave-labs/Checkmate/commit/091c36cbf338b673110b0806d76df26d52516468","https://github.com/bluewave-labs/Checkmate/releases/tag/v3.9.1"],"weaknesses":["CWE-400","CWE-770"],"ingestedAt":"2026-10-29T20:12:24.861Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/55xxx/CVE-2026-55241.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-55241","state":"PUBLISHED","datePublished":"2026-08-21T17:57:10.014Z","dateUpdated":"2026-08-25T11:51:15.776Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-06-16T16:44:00.624Z"},"containers":{"cna":{"title":"Checkmate: Pre-auth Denial of Service via File Upload on Registration","descriptions":[{"lang":"en","value":"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":[{"vendor":"bluewave-labs","product":"Checkmate","versions":[{"version":"< 3.9.1","status":"affected"}]}],"references":[{"url":"https://github.com/bluewave-labs/Checkmate/security/advisories/GHSA-9xvg-x28f-m78m","name":"https://github.com/bluewave-labs/Checkmate/security/advisories/GHSA-9xvg-x28f-m78m","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/bluewave-labs/Checkmate/commit/091c36cbf338b673110b0806d76df26d52516468","name":"https://github.com/bluewave-labs/Checkmate/commit/091c36cbf338b673110b0806d76df26d52516468","tags":["x_refsource_MISC"]},{"url":"https://github.com/bluewave-labs/Checkmate/releases/tag/v3.9.1","name":"https://github.com/bluewave-labs/Checkmate/releases/tag/v3.9.1","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"HIGH","baseScore":7.5,"baseSeverity":"HIGH","confidentialityImpact":"NONE","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-400","lang":"en","description":"CWE-400: Uncontrolled Resource Consumption","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-770","lang":"en","description":"CWE-770: Allocation of Resources Without Limits or Throttling","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-08-21T17:57:10.014Z"},"source":{"advisory":"GHSA-9xvg-x28f-m78m","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/bluewave-labs/Checkmate/security/advisories/GHSA-9xvg-x28f-m78m","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-08-25T11:47:48.710908Z","id":"CVE-2026-55241","options":[{"Exploitation":"poc"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-08-25T11:51:15.776Z"}}]}}}