{"api_version":"1","generated_at":"2026-07-24T00:13:53+00:00","cve":"CVE-2021-32656","urls":{"html":"https://cve.report/CVE-2021-32656","api":"https://cve.report/api/cve/CVE-2021-32656.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2021-32656","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2021-32656"},"summary":{"title":"CVE-2021-32656","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.","state":"PUBLIC","assigner":"security-advisories@github.com","published_at":"2021-06-01 22:15:00","updated_at":"2022-10-25 15:47:00"},"problem_types":["CWE-284"],"metrics":[],"references":[{"url":"https://security.gentoo.org/glsa/202208-17","name":"GLSA-202208-17","refsource":"GENTOO","tags":[],"title":"Nextcloud: Multiple Vulnerabilities (GLSA 202208-17) — Gentoo security","mime":"text/html","httpstatus":"200","archivestatus":"404"},{"url":"https://github.com/nextcloud/security-advisories/security/advisories/GHSA-j875-vr2q-h6x6","name":"https://github.com/nextcloud/security-advisories/security/advisories/GHSA-j875-vr2q-h6x6","refsource":"CONFIRM","tags":[],"title":"Trusted servers exchange can be triggered by attacker · Advisory · nextcloud/security-advisories · GitHub","mime":"text/html","httpstatus":"200","archivestatus":"404"},{"url":"https://hackerone.com/reports/1167853","name":"https://hackerone.com/reports/1167853","refsource":"MISC","tags":[],"title":"HackerOne","mime":"text/html","httpstatus":"200","archivestatus":"404"},{"url":"https://www.cve.org/CVERecord?id=CVE-2021-32656","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-32656","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[{"cve_year":"2021","cve_id":"32656","vulnerable":"1","versionEndIncluding":"","cpe1":"cpe","cpe2":"2.3","cpe3":"a","cpe4":"nextcloud","cpe5":"nextcloud_server","cpe6":"*","cpe7":"*","cpe8":"*","cpe9":"*","cpe10":"*","cpe11":"*","cpe12":"*","cpe13":"*"}],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[{"cve":"CVE-2021-32656","qid":"710590","title":"Gentoo Linux Nextcloud Multiple Vulnerabilities (GLSA 202208-17)"}]},"source_records":{"cve_program":{"CVE_data_meta":{"ASSIGNER":"security-advisories@github.com","ID":"CVE-2021-32656","STATE":"PUBLIC","TITLE":"Trusted servers exchange can be triggered by attacker"},"affects":{"vendor":{"vendor_data":[{"product":{"product_data":[{"product_name":"security-advisories","version":{"version_data":[{"version_value":"< 19.0.11"},{"version_value":">= 20.0.0, < 20.0.10"},{"version_value":">= 21.0.0, < 21.0.2"}]}}]},"vendor_name":"nextcloud"}]}},"data_format":"MITRE","data_type":"CVE","data_version":"4.0","description":{"description_data":[{"lang":"eng","value":"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."}]},"impact":{"cvss":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":8.6,"baseSeverity":"HIGH","confidentialityImpact":"HIGH","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"CHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N","version":"3.1"}},"problemtype":{"problemtype_data":[{"description":[{"lang":"eng","value":"CWE-284: Improper Access Control"}]}]},"references":{"reference_data":[{"name":"https://github.com/nextcloud/security-advisories/security/advisories/GHSA-j875-vr2q-h6x6","refsource":"CONFIRM","url":"https://github.com/nextcloud/security-advisories/security/advisories/GHSA-j875-vr2q-h6x6"},{"name":"https://hackerone.com/reports/1167853","refsource":"MISC","url":"https://hackerone.com/reports/1167853"},{"refsource":"GENTOO","name":"GLSA-202208-17","url":"https://security.gentoo.org/glsa/202208-17"}]},"source":{"advisory":"GHSA-j875-vr2q-h6x6","discovery":"UNKNOWN"}},"nvd":{"publishedDate":"2021-06-01 22:15:00","lastModifiedDate":"2022-10-25 15:47:00","problem_types":["CWE-284"],"metrics":{"baseMetricV3":{"cvssV3":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"CHANGED","confidentialityImpact":"HIGH","integrityImpact":"NONE","availabilityImpact":"NONE","baseScore":8.6,"baseSeverity":"HIGH"},"exploitabilityScore":3.9,"impactScore":4},"baseMetricV2":{"cvssV2":{"version":"2.0","vectorString":"AV:N/AC:L/Au:N/C:P/I:N/A:N","accessVector":"NETWORK","accessComplexity":"LOW","authentication":"NONE","confidentialityImpact":"PARTIAL","integrityImpact":"NONE","availabilityImpact":"NONE","baseScore":5},"severity":"MEDIUM","exploitabilityScore":10,"impactScore":2.9,"acInsufInfo":false,"obtainAllPrivilege":false,"obtainUserPrivilege":false,"obtainOtherPrivilege":false,"userInteractionRequired":false}},"configurations":{"CVE_data_version":"4.0","nodes":[{"operator":"OR","children":[],"cpe_match":[{"vulnerable":true,"cpe23Uri":"cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:*:*:*:*","versionEndExcluding":"19.0.11","cpe_name":[]},{"vulnerable":true,"cpe23Uri":"cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:*:*:*:*","versionStartIncluding":"20.0.0","versionEndExcluding":"20.0.10","cpe_name":[]},{"vulnerable":true,"cpe23Uri":"cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:*:*:*:*","versionStartIncluding":"21.0.0","versionEndExcluding":"21.0.2","cpe_name":[]}]}]}},"legacy_mitre":{"record":{"CveYear":"2021","CveId":"32656","Ordinal":"208044","Title":"CVE-2021-32656","CVE":"CVE-2021-32656","Year":"2021"},"notes":[{"CveYear":"2021","CveId":"32656","Ordinal":"1","NoteData":"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.","Type":"Description","Title":null},{"CveYear":"2021","CveId":"32656","Ordinal":"2","NoteData":"2021-06-01","Type":"Other","Title":"Published"},{"CveYear":"2021","CveId":"32656","Ordinal":"3","NoteData":"2021-06-01","Type":"Other","Title":"Modified"}]}}}