{"id":"CVE-2026-110863","summary":"Better Auth @better-auth/sso before 1.7.3 Authentication Bypass via Personal SSO Providers","details":"Better Auth @better-auth/sso from 1.7.0-rc.2 before 1.7.3 contains an authentication bypass vulnerability that allows authenticated users to sign in as other users by registering a personal SSO provider. Attackers can copy a legitimate provider's OIDC issuer or SAML entity ID and assert a victim's subject or NameID, because account lookup ignores providerId, creating sessions for victim accounts.","aliases":["GHSA-mx9r-x6ww-qjw9"],"modified":"2026-10-15T10:47:35.209970194Z","published":"2026-10-14T22:52:50.378Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/110xxx/CVE-2026-110863.json","cna_assigner":"VulnCheck","cwe_ids":["CWE-287"]},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/110xxx/CVE-2026-110863.json"},{"type":"ADVISORY","url":"https://github.com/better-auth/better-auth/security/advisories/GHSA-mx9r-x6ww-qjw9"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-110863"},{"type":"ADVISORY","url":"https://www.vulncheck.com/advisories/better-auth-better-auth-sso-before-1.7.3-authentication-bypass-via-personal-sso-providers"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/better-auth/better-auth","events":[{"introduced":"cc708e51bcb1d4c367d2bc6182e6fd7fd722ece8"},{"fixed":"597d39cb4aaaac1ad729051fbdd22a63b8ba8d8d"}],"database_specific":{"extracted_events":[{"introduced":"1.7.0-rc.2"},{"fixed":"1.7.3"}],"source":"AFFECTED_FIELD"}}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-110863.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N"}]}