better-auth Better Auth up to 1.6.10 Organization Plugin acceptInvitation invitation ID improper authorization

Summaryinfo

A vulnerability identified as critical has been detected in better-auth Better Auth up to 1.6.10. The impacted element is the function acceptInvitation of the component Organization Plugin. Performing a manipulation of the argument invitation ID results in improper authorization. This vulnerability was named CVE-2026-53514. The attack may be initiated remotely. There is no available exploit.

Detailsinfo

A vulnerability, which was classified as critical, was found in better-auth Better Auth up to 1.6.10. This affects the function acceptInvitation of the component Organization Plugin. The manipulation of the argument invitation ID with an unknown input leads to a improper authorization vulnerability. CWE is classifying the issue as CWE-285. The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

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.

The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2026-53514 since 06/09/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. It demands that the victim is doing some kind of user interaction. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1548.002 for this issue.

Upgrading to version 1.6.11 eliminates this vulnerability.

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Productinfo

Vendor

• better-auth

Name

• Better Auth

Version

• 1.6.0
• 1.6.1
• 1.6.2
• 1.6.3
• 1.6.4
• 1.6.5
• 1.6.6
• 1.6.7
• 1.6.8
• 1.6.9
• 1.6.10

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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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