Overview
CVE-2025-66551 is a medium-severity vulnerability affecting Nextcloud Tables, a powerful app that allows users to create and manage custom tables with individual columns. This flaw allows a malicious user to potentially move a column from their own table into a victim’s table without proper authorization. This could lead to data corruption, data theft, or other unintended consequences.
Technical Details
The vulnerability lies within the column management functionality of Nextcloud Tables. Prior to versions 0.8.6 and 0.9.3, insufficient authorization checks were performed when a user attempted to move a column between tables. A malicious user could exploit this by crafting a request that moves a column from their own table to a table belonging to another user. The lack of proper validation allows this unauthorized transfer to succeed.
CVSS Analysis
- CVE ID: CVE-2025-66551
- Severity: MEDIUM
- CVSS Score: 6.3
A CVSS score of 6.3 indicates a medium severity vulnerability. This is because while it requires a degree of user interaction (e.g., the victim needs to have tables created in Nextcloud Tables), the potential impact on data integrity and confidentiality is significant.
Possible Impact
The successful exploitation of this vulnerability could lead to several negative outcomes:
- Data Corruption: Moving a column with incompatible data types could corrupt the target table.
- Data Theft: Moving a column containing sensitive information could lead to unauthorized data access.
- Denial of Service: Corrupted data or unexpected data types could cause the application to malfunction, leading to a denial of service for the affected user.
- Reputational Damage: A successful attack could damage the reputation of the Nextcloud instance and the organization hosting it.
Mitigation or Patch Steps
To mitigate this vulnerability, it is highly recommended to upgrade your Nextcloud Tables app to one of the following versions:
- Version 0.8.6 or later
- Version 0.9.3 or later
You can update the app through the Nextcloud app store. Applying this update will patch the vulnerability and prevent unauthorized column transfers.
