CVE-2026-110862

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

State: Published
Severity: 9.3 Critical
Published: Oct 14, 2026
Updated: Oct 15, 2026
Reserved: Oct 14, 2026

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.

Scores

CVSS	Score	Vector	Source
4.0	9.3 Critical	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N	VulnCheck
3.1	9.1 Critical	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N	VulnCheck

Weaknesses

CWE-287 Improper Authentication

Affected Products

Product	Versions
better-authbetter-auth	1.4.0-beta.18 to before 1.7.7Affected 1.7.7Not affected

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 Linkthird-party-advisory

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