CVE-2025-66510 Nextcloud Server Contacts Search allowed users to retrieve contact information of other users beyond their contact list
Authenticated users can retrieve personal data of other users beyond their contact list due to missing access controls in the contacts search feature.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2025-66510?
CVE-2025-66510 is a medium-severity vulnerability in Nextcloud Nextcloud Server, published on 5 Dec 2025. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.
Official description
Nextcloud Server is a self hosted personal cloud system. In Nextcloud Server prior to 31.0.10 and 32.0.1 and Nextcloud Enterprise Server prior to 28.0.14.11, 29.0.16.8, 30.0.17.3, and 31.0.10, contacts search allowed to retrieve personal data of other users (emails, names, identifiers) without proper access control. This allows an authenticated user to retrieve information about accounts that are not related or added as contacts.
Weakness: CWE-359
Which versions are affected by CVE-2025-66510?
1 open source package ship an affected version, including nextcloud. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
nextcloud Bitnami | From 31.0.0 | 31.0.10, 32.0.1 |
Products include Nextcloud Nextcloud Server.
How do I fix CVE-2025-66510?
Upgrade nextcloud to a fixed version for your release line: 31.0.10 or 32.0.1.
Is CVE-2025-66510 being exploited?
There is no known exploitation of CVE-2025-66510 in the wild and no public exploit code.
Other vulnerabilities in Nextcloud Nextcloud Server
- CVE-2021-32802 Preview generation used third-party library not suited for user-generated content in Nextcloud server
- CVE-2023-26482 Scope of workflow operations is not validated in nextcloud server
- CVE-2018-3775 Auth bypass in Nextcloud Server
- CVE-2023-35172 Nextcloud Server password reset endpoint is not brute force protected
- CVE-2023-32320 Nextcloud Server's brute force protection allows someone to send more requests than intended
Sources
Also known as BIT-nextcloud-2025-66510, GHSA-495w-cqv6-wr59.