Vulnerability · Published Oct 14, 2026 · Assigned by VulnCheck

CVE-2026-110862Better Auth 1.4.0-beta.18 before 1.7.7 Authentication Bypass via Magic Link

Critical 9.1

In plain English

A critical-severity improper authentication in better-auth from better-auth. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 25% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)9.1Critical

Exploit odds (30 days)0.3%top 74.8% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

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.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
npm	better-auth	1.7.7	GHSA-965c-763c-88jm

Affected products (as reported)

Vendor	Product	Versions
better-auth	better-auth	1.4.0-beta.18 – before 1.7.7

Weakness: CWE-287 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

References

GitHub Security Advisory (GHSA-965c-763c-88jm) vendor-advisory
VulnCheck Advisory: Better Auth 1.4.0-beta.18 before 1.7.7 Authentication Bypass via Magic Link third-party-advisory