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.

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact High

Vulnerable System Integrity Impact High

Vulnerable System Availability Impact None

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact None

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
better-auth better-auth unaffected
Version Status Constraints
1.4.0-beta.18 affected < 1.7.7
1.7.7 unaffected —

No data.

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Project Subscriptions

Vendors Products
Better-auth Subscribe
Better Auth Subscribe
Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/better-auth/better-auth/security/advisories/GHSA-965c-763c-88jm cve-icon cve-icon
https://www.vulncheck.com/advisories/better-auth-1.4.0-beta.18-before-1.7.7-authentication-bypass-via-magic-link cve-icon cve-icon
History

Wed, 14 Oct 2026 23:00:00 +0000

Type Values Removed Values Added
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.
Title Better Auth 1.4.0-beta.18 before 1.7.7 Authentication Bypass via Magic Link
First Time appeared Better-auth
Better-auth better Auth
Weaknesses CWE-287
CPEs cpe:2.3:a:better-auth:better_auth:*:*:*:*:*:*:*:*
Vendors & Products Better-auth
Better-auth better Auth
References
Metrics cvssV3_1

{'score': 9.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N'}

cvssV4_0

{'score': 9.3, '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'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-10-14T22:52:46.811Z

Reserved: 2026-10-14T22:18:33.239Z

Link: CVE-2026-110862

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-10-14T23:17:27.673

Modified: 2026-10-14T23:17:27.673

Link: CVE-2026-110862

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses