{"id":"CVE-2026-67337","aliases":["EUVD-2026-51837","GHSA-8pwm-pjg9-4h92","GHSA-xg6x-h9c9-2m83"],"status":"published","title":"better-auth before 1.4.9 Two-Factor Authentication Bypass via session.cookieCache","description":"better-auth versions before 1.4.9 contain a two-factor authentication bypass vulnerability when session.cookieCache is enabled. Attackers with valid primary credentials can access authenticated routes without completing second-factor verification by exploiting premature session caching.","severity":{"version":"4.0","score":7.1,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-09","score":0.00462,"percentile":0.40332,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-288"],"published":"2026-04-03T03:29:59Z","modified":"2026-10-28T02:31:08Z","fixes":[{"ecosystem":"npm","package":"better-auth","fixed_in":["1.4.9"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"npm","package":"better-auth","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.4.9"}]}]},{"source":"osv","ecosystem":"npm","package":"better-auth","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"1.4.9"}]}]}],"products":[{"vendor":"better-auth","product":"better-auth"}],"references":[{"url":"https://github.com/better-auth/better-auth/security/advisories/GHSA-xg6x-h9c9-2m83","tags":["vendor-advisory","advisory","web"]},{"url":"https://www.vulncheck.com/advisories/better-auth-before-two-factor-authentication-bypass-via-session-cookiecache","tags":["third-party-advisory","advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-67337","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-8pwm-pjg9-4h92"},{"url":"https://github.com/advisories/GHSA-xg6x-h9c9-2m83"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/67xxx/CVE-2026-67337.json","tags":["advisory"]},{"url":"https://github.com/better-auth/better-auth","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-67337","title":"better-auth before 1.4.9 Two-Factor Authentication Bypass via session.cookieCache","description":"better-auth versions before 1.4.9 contain a two-factor authentication bypass vulnerability when session.cookieCache is enabled. Attackers with valid primary credentials can access authenticated routes without completing second-factor verification by exploiting premature session caching.","status":"published","published":"2026-08-01T12:22:18.034Z","modified":"2026-08-03T18:31:13.051Z","cvss":[{"version":"4.0","score":7.1,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N","level":"high","assessor":"cna"},{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N","level":"medium","assessor":"cna"}],"cwes":["CWE-288"],"updated_at":"2026-11-02T14:20:06.562031Z"}],"euvd":[{"id":"EUVD-2026-51837","description":"better-auth versions before 1.4.9 contain a two-factor authentication bypass vulnerability when session.cookieCache is enabled. Attackers with valid primary credentials can access authenticated routes without completing second-factor verification by exploiting premature session caching.","status":"published","published":"2026-08-01T12:22:18Z","modified":"2026-08-03T18:31:13Z","cvss":[{"version":"4.0","score":7.1,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N","level":"high"}],"updated_at":"2026-11-02T18:02:24.01774Z"}],"ghsa":[{"id":"GHSA-8pwm-pjg9-4h92","title":"better-auth versions before 1.4.9 contain a two-factor authentication bypass vulnerability when...","description":"better-auth versions before 1.4.9 contain a two-factor authentication bypass vulnerability when session.cookieCache is enabled. Attackers with valid primary credentials can access authenticated routes without completing second-factor verification by exploiting premature session caching.","status":"published","published":"2026-08-01T15:30:29Z","modified":"2026-08-01T15:30:36Z","cvss":[{"version":"4.0","score":7.1,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"high"},{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N","level":"medium"}],"cwes":["CWE-288"],"updated_at":"2026-11-02T15:10:01.548476Z"},{"id":"GHSA-xg6x-h9c9-2m83","title":"Better Auth Has Two-Factor Authentication Bypass via Premature Session Caching (session.cookieCache)","description":"### Summary\n\nUnder certain configurations, sessions may be considered valid before two-factor authentication (2FA) is fully completed. This can allow access to authenticated routes without verifying the second factor.\n\n---\n\n### Description\n\nWhen two-factor authentication is enabled, the authentication flow correctly identifies users who require additional verification and defers full authentication until the second factor is completed.\n\nHowever, when `session.cookieCache` is enabled, the session generated during the initial sign-in step may be cached as valid **prior to 2FA verification**. Subsequent session lookups may then return this cached session without re-evaluating the 2FA requirement.\n\nThis results in a situation where session validity can be established before all authentication constraints are satisfied.\n\n---\n\n### Impact\n\nAn attacker (or user) with valid primary credentials may gain access to protected application routes without completing the required second authentication factor.\n\nAny application using `better-auth` with both two-factor authentication and session cookie caching enabled may be affected.\n\n---\n\n### Mitigation\n\n* Upgrade to a version of `better-auth` that includes the fix for this issue.\n* Ensure that session caching does not treat sessions as fully authenticated until all required authentication steps, including 2FA, are completed.\n* As a temporary workaround, disable `session.cookieCache` when using two-factor authentication.","status":"published","published":"2026-04-03T03:29:59Z","modified":"2026-04-03T03:29:59Z","cvss":[{"version":"4.0","score":9.1,"vector":"CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N","level":"critical"}],"cwes":["CWE-288"],"updated_at":"2026-11-02T14:39:47.945242Z"}],"nvd":[{"id":"CVE-2026-67337","description":"better-auth versions before 1.4.9 contain a two-factor authentication bypass vulnerability when session.cookieCache is enabled. Attackers with valid primary credentials can access authenticated routes without completing second-factor verification by exploiting premature session caching.","status":"published","published":"2026-08-01T13:17:04.693Z","modified":"2026-09-08T20:34:34.997Z","cvss":[{"version":"4.0","score":7.1,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"high","assessor":"secondary"},{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N","level":"medium","assessor":"secondary"}],"cwes":["CWE-288"],"updated_at":"2026-11-02T14:12:34.290716Z"}],"osv":[{"id":"CVE-2026-67337","title":"better-auth before 1.4.9 Two-Factor Authentication Bypass via session.cookieCache","description":"better-auth versions before 1.4.9 contain a two-factor authentication bypass vulnerability when session.cookieCache is enabled. Attackers with valid primary credentials can access authenticated routes without completing second-factor verification by exploiting premature session caching.","status":"published","published":"2026-08-01T12:22:18.034Z","modified":"2026-10-28T02:31:08.000302306Z","cvss":[{"version":"4.0","score":7.1,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N","level":"high"}],"cwes":["CWE-288"],"updated_at":"2026-11-02T15:45:14.46177Z"},{"id":"GHSA-xg6x-h9c9-2m83","title":"Better Auth Has Two-Factor Authentication Bypass via Premature Session Caching (session.cookieCache)","description":"### Summary\n\nUnder certain configurations, sessions may be considered valid before two-factor authentication (2FA) is fully completed. This can allow access to authenticated routes without verifying the second factor.\n\n---\n\n### Description\n\nWhen two-factor authentication is enabled, the authentication flow correctly identifies users who require additional verification and defers full authentication until the second factor is completed.\n\nHowever, when `session.cookieCache` is enabled, the session generated during the initial sign-in step may be cached as valid **prior to 2FA verification**. Subsequent session lookups may then return this cached session without re-evaluating the 2FA requirement.\n\nThis results in a situation where session validity can be established before all authentication constraints are satisfied.\n\n---\n\n### Impact\n\nAn attacker (or user) with valid primary credentials may gain access to protected application routes without completing the required second authentication factor.\n\nAny application using `better-auth` with both two-factor authentication and session cookie caching enabled may be affected.\n\n---\n\n### Mitigation\n\n* Upgrade to a version of `better-auth` that includes the fix for this issue.\n* Ensure that session caching does not treat sessions as fully authenticated until all required authentication steps, including 2FA, are completed.\n* As a temporary workaround, disable `session.cookieCache` when using two-factor authentication.","status":"published","published":"2026-04-03T03:29:59Z","modified":"2026-08-02T03:56:49.020545992Z","cvss":[{"version":"4.0","score":9.1,"vector":"CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N","level":"critical"}],"cwes":["CWE-288"],"updated_at":"2026-11-02T15:46:59.835583Z"}]}}