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NVD Vulnerability Details :
CVE-2025-66550
Analyzed
More InfoOfficial Page
Source-security-advisories@github.com
View Known Exploited Vulnerability (KEV) details
Published At-05 Dec, 2025 | 17:16
Updated At-10 Dec, 2025 | 14:13

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.

CISA Catalog
Date AddedDue DateVulnerability NameRequired Action
N/A
Date Added: N/A
Due Date: N/A
Vulnerability Name: N/A
Required Action: N/A
Metrics
TypeVersionBase scoreBase severityVector
Secondary3.15.7MEDIUM
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:H/A:N
Type: Secondary
Version: 3.1
Base score: 5.7
Base severity: MEDIUM
Vector:
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:H/A:N
CPE Matches
Nextcloud GmbH
nextcloud
>>calendar>>Versions from 4.0.0(inclusive) to 4.7.17(exclusive)
cpe:2.3:a:nextcloud:calendar:*:*:*:*:*:*:*:*
Nextcloud GmbH
nextcloud
>>calendar>>Versions from 5.0.0(inclusive) to 5.2.4(exclusive)
cpe:2.3:a:nextcloud:calendar:*:*:*:*:*:*:*:*
Weaknesses
CWE IDTypeSource
CWE-241Primarysecurity-advisories@github.com
CWE ID: CWE-241
Type: Primary
Source: security-advisories@github.com
Evaluator Description
Evaluator Impact

Evaluator Solution

Vendor Statements
References
HyperlinkSourceResource
https://github.com/nextcloud/calendar/commit/63a6c398db01391eb9fd5297a0d4c3d6e614f769security-advisories@github.com
Patch
https://github.com/nextcloud/calendar/pull/6971security-advisories@github.com
Issue Tracking
https://github.com/nextcloud/security-advisories/security/advisories/GHSA-f29c-ppmv-8mcvsecurity-advisories@github.com
Patch
Vendor Advisory
https://hackerone.com/reports/3112033security-advisories@github.com
Issue Tracking
Vendor Advisory
Hyperlink: https://github.com/nextcloud/calendar/commit/63a6c398db01391eb9fd5297a0d4c3d6e614f769
Source: security-advisories@github.com
Resource:
Patch
Hyperlink: https://github.com/nextcloud/calendar/pull/6971
Source: security-advisories@github.com
Resource:
Issue Tracking
Hyperlink: https://github.com/nextcloud/security-advisories/security/advisories/GHSA-f29c-ppmv-8mcv
Source: security-advisories@github.com
Resource:
Patch
Vendor Advisory
Hyperlink: https://hackerone.com/reports/3112033
Source: security-advisories@github.com
Resource:
Issue Tracking
Vendor Advisory
Change History
0Changes found
Details not found