CVE-2025-66510: nextcloud nextcloud_server
Vulnerability summary
CVE-2025-66510 is a medium (CVSS 4.9) vulnerability in nextcloud nextcloud_server. EPSS estimates a 0.36% chance of exploitation in the next 30 days, higher than 28% of scored vulnerabilities.
Advisory lineage
Upstream 0 · Downstream 0 · Related 1Timeline
- 05-12-2025PublishedVulnerability first disclosed.
- 05-12-2025Last modifiedVulnerability information updated.
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.
CVSS metrics
3 scores · 3 sources · 1 version- CVE.orgCNA4.5MediumCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:H/I:N/A:NDiffers
- OSV · ChainguardEcosystem advisory · calculated4.5MediumCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:H/I:N/A:NDiffers
EPSS trend
Probability
0.36%
Chance of exploitation in the next 30 days
Percentile
28%
Versus all other CVEs
30-day change
0.00 pp
From 0.36% on 19-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Nextcloud2 products
- nextcloud_server≥ 28.0.0, < 28.0.14.11 | ≥ 29.0.0, < 29.0.16.8 | ≥ 30.0.0, < 30.0.17.3 | ≥ 31.0.0, < 31.0.10 | ≥ 32.0.0, < 32.0.1
- security-advisories≥ 32.0.0beta1, < 32.0.1 | < 31.0.10
Chainguard1 product
- nextcloud-server-30All versions (No fix recorded)
2 vendors · 3 products
References
5 links- github.com/nextcloud/security-advisories/security/advisories/GHSA-495w-cqv6-wr59X Refsource CONFIRMAdvisoryPatchVendor Advisory
