Security Digest · Critical advisory (no CVE assigned)
GHSA-xg6x-h9c9-2m83: Better Auth Has Two-Factor Authentication Bypass via Premature Session Caching (session.cookieCache)
Summary Under certain configurations, sessions may be considered valid before two-factor authentication (2FA) is fully completed.
CVSS 9.1 Critical GitHub-reviewed · critical
Should you act?
- Only if you depend on one of the packages below, directly or transitively, in a vulnerable version. Check your lockfile with
npm audit (or: npm ls <package>). - No CVE has been assigned, so it will not appear in CVE-based scanners that ignore GitHub advisories.
npm audit,pip-auditand Dependabot do read GitHub advisories.
Affected packages
| Ecosystem | Package | Vulnerable | First fixed |
|---|---|---|---|
| npm | better-auth | < 1.4.9 | 1.4.9 |
Details
Summary
Under 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.
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Description
When 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.
However, 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.
This results in a situation where session validity can be established before all authentication constraints are satisfied.
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CVSS: 9.1 (v4.0) 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
Sources and references
- GitHub Advisory GHSA-xg6x-h9c9-2m83 github.com
- github.com github.com