CVE-2025-66550

5.7 MEDIUM
Published: December 05, 2025 Modified: December 10, 2025
View on NVD

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.

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:H/A:N

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://github.com/nextcloud/calendar/commit/63a6c398db01391eb9fd5297a0d4c3d6e614f769
Source: security-advisories@github.com
Patch
https://github.com/nextcloud/calendar/pull/6971
Source: security-advisories@github.com
Issue Tracking
https://github.com/nextcloud/security-advisories/security/advisories/GHSA-f29c-ppmv-8mcv
Source: security-advisories@github.com
Patch Vendor Advisory
https://hackerone.com/reports/3112033
Source: security-advisories@github.com
Issue Tracking Vendor Advisory

4 reference(s) from NVD

Quick Stats

CVSS v3 Score
5.7 / 10.0
EPSS (Exploit Probability)
0.0%
4th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)

CWE-241

Affected Vendors

nextcloud

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