{"id":"CVE-2026-53909","state":"PUBLISHED","title":"Arbitrary File Upload in MCO","description":"MCO does not correctly validate types of uploaded files. File upload validation functionality relies only on client-side checks, which can be bypassed. An authorized, low-privileged attacker can upload files with arbitrary types to the server.\n\nBecause vendor contact attempts were unsuccessful, the vulnerability has only been confirmed in version 25.3.3.1 but may also affect other versions.","publishedAt":"2026-07-01T11:59:26.104Z","updatedAt":"2026-07-01T13:37:13.787Z","severity":{"score":5.3,"label":"Medium","version":"4.0","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N","source":"CERT-PL"},"assigner":"CERT-PL","products":["MyComplianceOffice MCO"],"affected":[{"vendor":"MyComplianceOffice","product":"MCO","defaultStatus":"unknown","versions":[{"version":"25.3.3.1","status":"affected","versionType":"custom"}]}],"references":["https://cert.pl/en/posts/2026/07/CVE-2026-53902","https://mco.mycomplianceoffice.com/"],"weaknesses":["CWE-434"],"ingestedAt":"2026-10-29T20:12:16.098Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/53xxx/CVE-2026-53909.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-53909","state":"PUBLISHED","datePublished":"2026-07-01T11:59:26.104Z","dateUpdated":"2026-07-01T13:37:13.787Z","assignerShortName":"CERT-PL","assignerOrgId":"4bb8329e-dd38-46c1-aafb-9bf32bcb93c6","dateReserved":"2026-06-11T07:44:52.179Z"},"containers":{"cna":{"title":"Arbitrary File Upload in MCO","descriptions":[{"lang":"en","value":"MCO does not correctly validate types of uploaded files. File upload validation functionality relies only on client-side checks, which can be bypassed. An authorized, low-privileged attacker can upload files with arbitrary types to the server.\n\nBecause vendor contact attempts were unsuccessful, the vulnerability has only been confirmed in version 25.3.3.1 but may also affect other versions."}],"affected":[{"vendor":"MyComplianceOffice","product":"MCO","defaultStatus":"unknown","versions":[{"version":"25.3.3.1","status":"affected","versionType":"custom"}]}],"references":[{"url":"https://cert.pl/en/posts/2026/07/CVE-2026-53902","tags":["third-party-advisory"]},{"url":"https://mco.mycomplianceoffice.com/","tags":["product"]}],"metrics":[{"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}],"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"LOW","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","subConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","subIntegrityImpact":"LOW","vulnAvailabilityImpact":"NONE","subAvailabilityImpact":"NONE","exploitMaturity":"NOT_DEFINED","Safety":"NOT_DEFINED","Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","valueDensity":"NOT_DEFINED","vulnerabilityResponseEffort":"NOT_DEFINED","providerUrgency":"NOT_DEFINED","version":"4.0","baseSeverity":"MEDIUM","baseScore":5.3,"vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-434","lang":"en","description":"CWE-434 Unrestricted Upload of File with Dangerous Type","type":"CWE"}]}],"providerMetadata":{"shortName":"CERT-PL","orgId":"4bb8329e-dd38-46c1-aafb-9bf32bcb93c6","dateUpdated":"2026-07-01T11:59:26.104Z"},"credits":[{"lang":"en","value":"Hubert Decyusz (AFINE Team)","type":"finder"}],"source":{"discovery":"EXTERNAL"},"x_generator":{"engine":"Vulnogram 0.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-07-01T13:37:06.566970Z","id":"CVE-2026-53909","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-07-01T13:37:13.787Z"}}]}}}