Auth bypass in Better-Auth
CVE-2026-53516
Better Auth is an authentication and authorization library for TypeScript. Prior to 1.6.11, Better Auth's OAuth callback auto-link gate in handleOAuthUserInfo accepts implicit account linking when the OAuth provider asserts email_verified: true without requiring the local user row's emailVerified field to also be true, allowing an attacker who pre-registers a victim email through /sign-up/email to bind the victim's OAuth identity to the attacker's account. The same primitive affects one-tap, and emailAndPassword.requireEmailVerification: true does not mitigate the link-time verification change. This issue is fixed in version 1.6.11.
Vulnerability class: Broken Authentication
EPSS: 0.002 (13.9th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 8.3 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:L.
Affected products
- Better-auth — versions < 1.6.11
- Better-auth Better_auth
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Mitigation, Vendor Advisory)
- security-advisories@github.com (Patch, x_refsource_MISC, Issue Tracking)
- security-advisories@github.com (Patch, x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC, Release Notes)
Frequently asked questions
- What is CVE-2026-53516?
- CVE-2026-53516 is a high-severity vulnerability in Better-Auth, classified under Improper Authentication. CVSS score: 8.3/10. Published 2026-07-15.
- How severe is CVE-2026-53516?
- High severity. CVSS v3 base score is 8.3 out of 10.