{"id":"CVE-2023-39953","summary":"Issuer not verified from obtained token in user_oidc","details":"user_oidc provides the OIDC connect user backend for Nextcloud, an open-source cloud platform. Starting in version 1.0.0 and prior to version 1.3.3, missing verification of the issuer would have allowed an attacker to perform a man-in-the-middle attack returning corrupted or known token they also have access to. user_oidc 1.3.3 contains a patch. No known workarounds are available.","aliases":["GHSA-xx3h-v363-q36j"],"modified":"2026-04-10T05:00:32.480113Z","published":"2023-08-10T13:55:19.957Z","database_specific":{"cna_assigner":"GitHub_M","cwe_ids":["CWE-303"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/39xxx/CVE-2023-39953.json"},"references":[{"type":"WEB","url":"https://hackerone.com/reports/2021684"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/39xxx/CVE-2023-39953.json"},{"type":"ADVISORY","url":"https://github.com/nextcloud/security-advisories/security/advisories/GHSA-xx3h-v363-q36j"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2023-39953"},{"type":"FIX","url":"https://github.com/nextcloud/user_oidc/pull/642"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/nextcloud/user_oidc","events":[{"introduced":"2b27bd81899d8607f82ad41c2831bef91db835a5"},{"fixed":"3ff24f81b96792d96a2647d7b1f857b891c84643"}]}],"versions":["v1.0.0","v1.1.0","v1.2.0","v1.2.1","v1.3.0","v1.3.1","v1.3.2"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2023-39953.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N"}]}