Listen to this Post
How the mentioned CVE works:
CVE-2025-66545 is a permission bypass vulnerability in the Nextcloud Groupfolders application, which provides admin-configured shared folders for groups. In affected versions, the access control mechanism for the trash bin functionality is flawed. Users with read-only permissions to a group folder are incorrectly allowed to restore deleted files from the trash bin. Typically, only users with write or delete permissions should perform such actions, but the application fails to enforce these checks during trash restoration requests. This occurs due to insufficient server-side validation in the Groupfolders plugin, where the restore endpoint does not verify if the user has requisite write access. When a read-only user sends a crafted HTTP POST request to the restore API endpoint with a valid file ID, the system processes the request without proper authorization. The vulnerability stems from missing permission checks in the code handling trash operations, allowing bypass of intended restrictions. Exploitation requires that the user has read access to the group folder and knowledge of the trash bin interface. This can lead to unauthorized recovery of deleted files, potentially restoring sensitive data without approval. The issue affects multiple version branches before the fixes, compromising data integrity and access controls. The patches add proper permission validation to ensure only users with write permissions can restore files.
Platform: Nextcloud Groupfoldors
Version: Prior fixed versions
Vulnerability: Permission bypass restoration
Severity: Medium
Date: 2025-12-05
Prediction: Patched 2025-12-05
What Undercode Say:
Analytics:
Check Nextcloud version
sudo -u www-data php occ status
List Groupfolders app
sudo -u www-data php occ app:list
Update Groupfolders app
sudo -u www-data php occ app:update groupfolders
How Exploit:
Send restore request:
curl -X POST -H “OCS-APIRequest: true” -u user:pass “https://nextcloud.example.com/apps/groupfolders/trash/restore?fileId=123”
Protection from this CVE
Update to fixed versions: 14.0.11, 15.3.12, 16.0.15, 17.0.14, 18.1.8, 19.1.8, 20.1.2. Review user permissions. Restrict trash access.
Impact:
Unauthorized file restoration. Data integrity compromise. Access control bypass.
🎯Let’s Practice Exploiting & Learn Patching For Free:
Sources:
Reported By: nvd.nist.gov
Extra Source Hub:
Undercode
