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TI-2026-38588 Aliases CVE-2026-53514GHSA-fmh4-wcc4-5jm3

Better Auth: Unauthorized invitation acceptance via unverified email match in organization plugin

Priority LOW 35CWE-287Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
Required
Attack complexity
High
Impact type
Security bypass
Confidentiality · integrity · availability
High · High · None
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-287.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00201 10th percentileScored 2026-11-07
Fix Fixed better-auth (better-auth): 1.6.11better-auth (npm): 1.6.11

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
better-authbetter-authbefore 1.6.111.6.11Patch availableCNA
—better-auth (npm)before 1.6.111.6.11Patch availableGHSA-fmh4-wcc4-5jm3
  • better-auth Vendorbetter-auth Affected before 1.6.11 Fixed in 1.6.11 Patch available CNA
  • better-auth (npm) Vendor— Affected before 1.6.11 Fixed in 1.6.11 Patch available GHSA-fmh4-wcc4-5jm3

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:better-auth:better_auth:*:*:*:*:*:node.js:*:*before 1.6.11; 1.6.14Vulnerablebetter-auth
  • cpe:2.3:a:better-auth:better_auth:*:*:*:*:*:node.js:*:* Versions before 1.6.11; 1.6.14 Vulnerable ·better-auth

Remediation

  • Fix · CNA better-auth (better-auth) Fixed in 1.6.11
  • Fix · GHSA-fmh4-wcc4-5jm3 better-auth (npm) Fixed in 1.6.11 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-53514
  2. 2026-10-03 Alias added: GHSA-fmh4-wcc4-5jm3

References

Patch 2

Advisory 2

Other 2

  • TI-2025-20000 Beter Auth has an Open Redirect via Scheme-Less Callback Parameter CVSS 4.0MEDIUM 6.9
  • TI-2026-38586 Better Auth: OAuth refresh-token replay via missing client authentication on oidc-provider and mcp plugins CVSS 4.0CRITICAL 9.1
  • TI-2026-38587 Better Auth: Server-side request forgery via unvalidated OIDC endpoints on @better-auth/sso provider registration CVSS 3.1CRITICAL 9.6
  • TI-2026-38591 Better Auth OAuth Provider: Refresh Token Rotation Race Condition Allows Concurrent Replay and Token Family Forking CVSS 3.1HIGH 8.1
  • TI-2026-38590 Better Auth: Account takeover via OAuth auto-link to unverified pre-registered email CVSS 3.1HIGH 8.3
  • TI-2026-38592 Better Auth OAuth Provider: Race Condition in Authorization Code Exchange Enables Multi-Use Code Redemption CVSS 4.0HIGH 7.6
See all 9 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences