Improper access control in Deck - CVE-2025-66557
Published: December 5, 2025
Vulnerability identifier: #VU119221
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2025-66557
CWE-ID: CWE-284
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Nextcloud
Affected software:
Deck
Deck
Detailed vulnerability description
The vulnerability allows a remote attacker to gain unauthorized access to otherwise restricted functionality.
The vulnerability exists due to a bug in the permission logic. A remote user can bypass implemented security restrictions and modify the permissions of other recipients.
How to mitigate CVE-2025-66557
Install updates from vendor's website.