CVE-2026-110862 PUBLISHED

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

Assigner: VulnCheck
Reserved: 14.10.2026 Published: 14.10.2026 Updated: 15.10.2026

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.

CVSS Vector: 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
CVSS Score: 9.3

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	High	Confidentiality	None
Attack Complexity	Low	Integrity	High	Integrity	None
Attack Requirements	None	Availability	None	Availability	None
Privileges Required	None
User Interaction	None

CVSS 4.0

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
CVSS Score: 9.1

Attack Vector	Network	Scope	Unchanged
Attack Complexity	Low	Confidentiality Impact	High
Privileges Required	None	Integrity Impact	High
User Interaction	None	Availability Impact	None

CVSS 3.1

Product Status

Vendor	better-auth
Product	better-auth
Versions	Default: unaffected affected from 1.4.0-beta.18 to 1.7.7 (excl.) Version 1.7.7 is unaffected

CVE-2026-110862 PUBLISHED

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

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Product Status

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References

Problem Types