Unrated severityNVD Advisory· Published Dec 5, 2025· Updated Dec 5, 2025
Nextcloud Calendar attachments of local files are offered to downloaded
CVE-2025-66550
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.
Affected products
2- Range: >= 4.7 <4.7.17, >= 5.0 <5.2.4
- nextcloud/security-advisoriesv5Range: >= 5.0.0-rc.1, < 5.2.4
Patches
0No patches discovered yet.
Vulnerability mechanics
AI mechanics synthesis has not run for this CVE yet.
References
4- github.com/nextcloud/calendar/commit/63a6c398db01391eb9fd5297a0d4c3d6e614f769mitrex_refsource_MISC
- github.com/nextcloud/calendar/pull/6971mitrex_refsource_MISC
- github.com/nextcloud/security-advisories/security/advisories/GHSA-f29c-ppmv-8mcvmitrex_refsource_CONFIRM
- hackerone.com/reports/3112033mitrex_refsource_MISC
News mentions
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