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
Published · last modified .
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.
EPSS exploit prediction
EPSS: 0.003 (20.4th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 20th percentile — 20.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000
Affected products
- Better-Auth — versions < 1.6.11
- Better-Auth Better Auth
Weakness classification (CWE)
References
- github.com/better-auth/better-auth/security/advisories/GHSA-g38m-r43w-p2q7 (Mitigation, Vendor Advisory)
- github.com/better-auth/better-auth/pull/9578 (Patch, Issue Tracking)
- github.com/better-auth/better-auth/commit/da7e50beee849c59a2ed1ec6b3a38cc6ab9fb… (Patch)
- github.com/better-auth/better-auth/releases/tag/v1.6.11 (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.