Vulnerability in Nextcloud Security-advisories
CVE-2025-66550
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…
EPSS: 0.000 (7.3th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 5.7 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:H/A:N.
Affected products
- Nextcloud Security-advisories — versions >= 5.0.0-rc.1, < 5.2.4, < 4.7.17
Weakness classification (CWE)
References
- https://github.com/nextcloud/security-advisories/security/advisories/GHSA-f29c-ppmv-8mcv (x_refsource_CONFIRM)
- https://github.com/nextcloud/calendar/pull/6971 (x_refsource_MISC)
- https://github.com/nextcloud/calendar/commit/63a6c398db01391eb9fd5297a0d4c3d6e614f769 (x_refsource_MISC)
- https://hackerone.com/reports/3112033 (x_refsource_MISC)
Frequently asked questions
- What is CVE-2025-66550?
- CVE-2025-66550 is a medium-severity vulnerability in Nextcloud Security-advisories, classified under CWE-241. CVSS score: 5.7/10. Published 2025-12-05.
- How severe is CVE-2025-66550?
- Medium severity. CVSS v3 base score is 5.7 out of 10.