{"id":"CVE-2025-66550","state":"PUBLISHED","title":"Nextcloud Calendar attachments of local files are offered to downloaded","description":"Nextcloud Calendar is a calendar app for Nextcloud. Prior to 4.7.17 and 5.2.4, when a malicious user creates a calendar event with a crafted attachment that links to a download link of a file on the same Nextcloud server, the file would be downloaded without the user confirming the action. This vulnerability is fixed in 4.7.17 and 5.2.4.","publishedAt":"2025-12-05T16:56:44.680Z","updatedAt":"2025-12-05T18:41:24.347Z","severity":{"score":5.7,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:H/A:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["nextcloud security-advisories"],"affected":[{"vendor":"nextcloud","product":"security-advisories","versions":[{"version":">= 5.0.0-rc.1, < 5.2.4","status":"affected"},{"version":"< 4.7.17","status":"affected"}]}],"references":["https://github.com/nextcloud/security-advisories/security/advisories/GHSA-f29c-ppmv-8mcv","https://github.com/nextcloud/calendar/pull/6971","https://github.com/nextcloud/calendar/commit/63a6c398db01391eb9fd5297a0d4c3d6e614f769","https://hackerone.com/reports/3112033"],"weaknesses":["CWE-241"],"ingestedAt":"2026-10-29T20:09:56.034Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2025/66xxx/CVE-2025-66550.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-66550","state":"PUBLISHED","datePublished":"2025-12-05T16:56:44.680Z","dateUpdated":"2025-12-05T18:41:24.347Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2025-12-04T15:57:22.034Z"},"containers":{"cna":{"title":"Nextcloud Calendar attachments of local files are offered to downloaded","descriptions":[{"lang":"en","value":"Nextcloud Calendar is a calendar app for Nextcloud. Prior to 4.7.17 and 5.2.4, when a malicious user creates a calendar event with a crafted attachment that links to a download link of a file on the same Nextcloud server, the file would be downloaded without the user confirming the action. This vulnerability is fixed in 4.7.17 and 5.2.4."}],"affected":[{"vendor":"nextcloud","product":"security-advisories","versions":[{"version":">= 5.0.0-rc.1, < 5.2.4","status":"affected"},{"version":"< 4.7.17","status":"affected"}]}],"references":[{"url":"https://github.com/nextcloud/security-advisories/security/advisories/GHSA-f29c-ppmv-8mcv","name":"https://github.com/nextcloud/security-advisories/security/advisories/GHSA-f29c-ppmv-8mcv","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/nextcloud/calendar/pull/6971","name":"https://github.com/nextcloud/calendar/pull/6971","tags":["x_refsource_MISC"]},{"url":"https://github.com/nextcloud/calendar/commit/63a6c398db01391eb9fd5297a0d4c3d6e614f769","name":"https://github.com/nextcloud/calendar/commit/63a6c398db01391eb9fd5297a0d4c3d6e614f769","tags":["x_refsource_MISC"]},{"url":"https://hackerone.com/reports/3112033","name":"https://hackerone.com/reports/3112033","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":5.7,"baseSeverity":"MEDIUM","confidentialityImpact":"NONE","integrityImpact":"HIGH","privilegesRequired":"LOW","scope":"UNCHANGED","userInteraction":"REQUIRED","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:H/A:N","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-241","lang":"en","description":"CWE-241: Improper Handling of Unexpected Data Type","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2025-12-05T16:56:44.680Z"},"source":{"advisory":"GHSA-f29c-ppmv-8mcv","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2025-12-05T18:37:20.458733Z","id":"CVE-2025-66550","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":"2025-12-05T18:41:24.347Z"}}]}}}