CVE-2021-32727

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Clients using the Nextcloud end-to-end encryption feature download the public and private key via an API endpoint. In versions prior to 3.16.1, the Nextcloud Android client skipped a step that involved the client checking if a private key belonged to a previously downloaded public certificate. If the Nextcloud instance served a malicious public key, the data would be encrypted for this key and thus could be accessible to a malicious actor. The vulnerability is patched in version 3.16.1. As a workaround, do not add additional end-to-end encrypted devices to a user account."}]}, "impact": {"cvss": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 5.7, "baseSeverity": "MEDIUM", "confidentialityImpact": "HIGH", "integrityImpact": "NONE", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "REQUIRED", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N", "version": "3.1"}}, "problemtype": {"problemtype_data": [{"description": [{"lang": "eng", "value": "CWE-295: Improper Certificate Validation"}]}]}, "references": {"reference_data": [{"name": "https://github.com/nextcloud/security-advisories/security/advisories/GHSA-5v33-r9cm-7736", "refsource": "CONFIRM", "url": "https://github.com/nextcloud/security-advisories/security/advisories/GHSA-5v33-r9cm-7736"}, {"name": "https://github.com/nextcloud/android/pull/8438", "refsource": "MISC", "url": "https://github.com/nextcloud/android/pull/8438"}, {"name": "https://hackerone.com/reports/1189162", "refsource": "MISC", "url": "https://hackerone.com/reports/1189162"}, {"name": "https://github.com/nextcloud/end_to_end_encryption_rfc/blob/7f002996397faefb664019a97ebb0a1e210f64f0/RFC.md#further-devices", "refsource": "MISC", "url": "https://github.com/nextcloud/end_to_end_encryption_rfc/blob/7f002996397faefb664019a97ebb0a1e210f64f0/RFC.md#further-devices"}]}, "source": {"advisory": "GHSA-5v33-r9cm-7736", "discovery": "UNKNOWN"}}}, "adp": [{"providerMetadata": {"orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2024-08-03T23:33:54.870Z"}, "title": "CVE Program Container", "references": [{"tags": ["x_refsource_CONFIRM", "x_transferred"], "url": "https://github.com/nextcloud/security-advisories/security/advisories/GHSA-5v33-r9cm-7736"}, {"tags": ["x_refsource_MISC", "x_transferred"], "url": "https://github.com/nextcloud/android/pull/8438"}, {"tags": ["x_refsource_MISC", "x_transferred"], "url": "https://hackerone.com/reports/1189162"}, {"tags": ["x_refsource_MISC", "x_transferred"], "url": "https://github.com/nextcloud/end_to_end_encryption_rfc/blob/7f002996397faefb664019a97ebb0a1e210f64f0/RFC.md#further-devices"}]}]}, "cveMetadata": {"assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "assignerShortName": "GitHub_M", "cveId": "CVE-2021-32727", "datePublished": "2021-07-12T20:40:13.000Z", "dateReserved": "2021-05-12T00:00:00.000Z", "dateUpdated": "2024-08-03T23:33:54.870Z", "state": "PUBLISHED"}, "dataType": "CVE_RECORD", "dataVersion": "5.1"}

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{"affected": [{"affectedData": [{"product": "security-advisories", "vendor": "nextcloud", "versions": [{"status": "affected", "version": "< 3.16.1"}]}], "source": "security-advisories@github.com"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:nextcloud:nextcloud:*:*:*:*:*:android:*:*", "matchCriteriaId": "8387BECC-5B20-4A16-9641-E91178BFA60D", "versionEndExcluding": "3.16.1", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "Nextcloud Android Client is the Android client for Nextcloud. Clients using the Nextcloud end-to-end encryption feature download the public and private key via an API endpoint. In versions prior to 3.16.1, the Nextcloud Android client skipped a step that involved the client checking if a private key belonged to a previously downloaded public certificate. If the Nextcloud instance served a malicious public key, the data would be encrypted for this key and thus could be accessible to a malicious actor. The vulnerability is patched in version 3.16.1. As a workaround, do not add additional end-to-end encrypted devices to a user account."}, {"lang": "es", "value": "Nextcloud Android Client es el cliente Android para Nextcloud. Unos clientes que usan la funcionalidad end-to-end encryption de Nextcloud descargan la clave p\u00fablica y privada por medio de un endpoint de la API. En versiones anteriores a 3.16.1, el cliente Android de Nextcloud se saltaba un paso que implicaba que el cliente comprobara si una clave privada pertenec\u00eda a un certificado p\u00fablico previamente descargado. Si la instancia de Nextcloud serv\u00eda una clave p\u00fablica maliciosa, los datos estar\u00edan cifrados para esta clave y, por tanto, podr\u00edan ser accesibles para un actor malicioso. La vulnerabilidad est\u00e1 parcheada en la versi\u00f3n 3.16.1. Como soluci\u00f3n alternativa, no a\u00f1ada dispositivos cifrados de extremo a extremo adicionales a una cuenta de usuario"}], "id": "CVE-2021-32727", "lastModified": "2026-06-17T03:53:30.623", "metrics": {"cvssMetricV2": [{"acInsufInfo": false, "baseSeverity": "MEDIUM", "cvssData": {"accessComplexity": "LOW", "accessVector": "NETWORK", "authentication": "NONE", "availabilityImpact": "NONE", "baseScore": 5.0, "confidentialityImpact": "PARTIAL", "integrityImpact": "NONE", "vectorString": "AV:N/AC:L/Au:N/C:P/I:N/A:N", "version": "2.0"}, "exploitabilityScore": 10.0, "impactScore": 2.9, "obtainAllPrivilege": false, "obtainOtherPrivilege": false, "obtainUserPrivilege": false, "source": "nvd@nist.gov", "type": "Primary", "userInteractionRequired": false}], "cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 5.7, "baseSeverity": "MEDIUM", "confidentialityImpact": "HIGH", "integrityImpact": "NONE", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "REQUIRED", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N", "version": "3.1"}, "exploitabilityScore": 2.1, "impactScore": 3.6, "source": "security-advisories@github.com", "type": "Secondary"}, {"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 7.5, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 3.6, "source": "nvd@nist.gov", "type": "Primary"}]}, "published": "2021-07-12T21:15:07.817", "references": [{"source": "security-advisories@github.com", "tags": ["Third Party Advisory"], "url": "https://github.com/nextcloud/android/pull/8438"}, {"source": "security-advisories@github.com", "tags": ["Third Party Advisory"], "url": "https://github.com/nextcloud/end_to_end_encryption_rfc/blob/7f002996397faefb664019a97ebb0a1e210f64f0/RFC.md#further-devices"}, {"source": "security-advisories@github.com", "tags": ["Third Party Advisory"], "url": "https://github.com/nextcloud/security-advisories/security/advisories/GHSA-5v33-r9cm-7736"}, {"source": "security-advisories@github.com", "tags": ["Permissions Required"], "url": "https://hackerone.com/reports/1189162"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Third Party Advisory"], "url": "https://github.com/nextcloud/android/pull/8438"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Third Party Advisory"], "url": "https://github.com/nextcloud/end_to_end_encryption_rfc/blob/7f002996397faefb664019a97ebb0a1e210f64f0/RFC.md#further-devices"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Third Party Advisory"], "url": "https://github.com/nextcloud/security-advisories/security/advisories/GHSA-5v33-r9cm-7736"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Permissions Required"], "url": "https://hackerone.com/reports/1189162"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Modified", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-295"}], "source": "security-advisories@github.com", "type": "Secondary"}, {"description": [{"lang": "en", "value": "CWE-295"}], "source": "nvd@nist.gov", "type": "Primary"}]}

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