---
id: CVE-2026-110862
title: >-
  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
summary: >-
  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 …
severity: critical
cvss: 9.1
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N'
cwe:
  - CWE-287
vendor: better-auth
product: better-auth
affected:
  - better-auth >= 1.4.0-beta.18 < 1.7.7
published: '2026-10-14'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T18:25:45.343'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-110862'
references:
  - url: >-
      https://github.com/better-auth/better-auth/security/advisories/GHSA-965c-763c-88jm
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/better-auth-1.4.0-beta.18-before-1.7.7-authentication-bypass-via-magic-link
    label: disclosure@vulncheck.com
tags:
  - nvd
  - cve.org
epss: 0.00321
epssPercentile: 0.24957
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: total
  timestamp: '2026-10-15T13:33:51.055902Z'
ingestedAt: '2026-10-15T00:02:07.186Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.