{"cve":"CVE-2021-32656","nvd":{"published":"2021-06-01T22:15:08.173","modified":"2026-06-17T03:53:21.657","status":"Modified","description":"Nextcloud Server is a Nextcloud package that handles data storage. A vulnerability in federated share exists in versions prior to 19.0.11, 20.0.10, and 21.0.2. An attacker can gain access to basic information about users of a server by accessing a public link that a legitimate server user added as a federated share. This happens because Nextcloud supports sharing registered users with other Nextcloud servers, which can be done automatically when selecting the \"Add server automatically once a federated share was created successfully\" setting. The vulnerability is patched in versions 19.0.11, 20.0.10, and 21.0.2 As a workaround, disable \"Add server automatically once a federated share was created successfully\" in the Nextcloud settings.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N","score":8.6},"cwes":["CWE-284"],"references":["https://github.com/nextcloud/security-advisories/security/advisories/GHSA-j875-vr2q-h6x6","https://hackerone.com/reports/1167853","https://security.gentoo.org/glsa/202208-17","https://github.com/nextcloud/security-advisories/security/advisories/GHSA-j875-vr2q-h6x6","https://hackerone.com/reports/1167853"],"products":["nextcloud:nextcloud_server"],"source":"nvd","synced_at":"2026-10-19T21:18:09.669877188+00:00"},"epss":{"cve":"CVE-2021-32656","score":0.01841,"percentile":0.78997,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}