Vulnerability in Nextcloud Server
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 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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 4.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:H/I:N/A:N.
EPSS exploit prediction
EPSS: 0.004 (27.0th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 27th percentile — 27.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: +0.000
Affected products
- Nextcloud Server
- Nextcloud Security-Advisories — versions >= 32.0.0beta1, < 32.0.1, < 31.0.10
Weakness classification (CWE)
References
- github.com/nextcloud/security-advisories/security/advisories/GHSA-495w-cqv6-wr59 (Patch, Vendor Advisory)
- github.com/nextcloud/server/pull/55657 (Issue Tracking)
- github.com/nextcloud/server/commit/e4866860cbf24a746eb8a125587262a4c8831c57 (Patch)
Frequently asked questions
- What is CVE-2025-66510?
- CVE-2025-66510 is a medium-severity vulnerability in Nextcloud Server, classified under Exposure of Private Personal Information to an Unauthorized Actor. CVSS score: 4.5/10. Published 2025-12-05.
- How severe is CVE-2025-66510?
- Medium severity. CVSS v3 base score is 4.5 out of 10.