CVE-2025-66510: Nextcloud Server is a self hosted personal cloud system. In Nextcloud Server prior to 31.0.10 and 32.0.1 and Nextcloud…
CVE-2025-66510 · Severity: medium · CVSS 4.5 · Published 2025-12-05
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.
No. Junglewise Threat Intelligence has no report of CVE-2025-66510 being exploited in the wild.
How severe is CVE-2025-66510?
Medium severity, with a CVSS score of 4.5, published 5 December 2025.
Which products and versions are affected?
Nextcloud Server. The advisory does not name versions.
Is there a fix for CVE-2025-66510?
No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
Am I affected by CVE-2025-66510?
Check whether you run Nextcloud Server. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.