Auth bypass in Better-Auth
CVE-2026-110862
Better Auth from 1.4.0-beta.18 before 1.7.7 contains an authentication bypass vulnerability that allows unauthenticated attackers to sign in as other users by reusing OAuth state values as Magic Link tokens. Attackers can start an OAuth sign-in with a victim's email and submit the returned state to Magic Link verification, gaining sessions or creating falsely email-verified accounts.
Vulnerability class: Broken Authentication
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- github.com/better-auth/better-auth/security/advisories/GHSA-965c-763c-88jm (vendor-advisory)
- www.vulncheck.com/advisories/better-auth-1.4.0-beta.18-before-1.7.7-authenticat… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-110862?
- CVE-2026-110862 is a critical-severity vulnerability in Better-Auth, classified under Improper Authentication. CVSS score: 9.1/10. Published 2026-10-14.
- How severe is CVE-2026-110862?
- Critical severity. CVSS v3 base score is 9.1 out of 10.