authdrift

Find OAuth handlers that will break when users rename their Gmail.

On 31 March 2026, Google began letting users rename their primary Gmail address. Every OAuth integration that uses email as the user lookup key will silently create a duplicate account when a user renames. Most do.

authdrift is a static analysis tool that scans your codebase for the exact patterns that explode on a Gmail rename — and on the ~0.04% baseline sub-claim drift Truffle Security documented in January 2025.

Install

pip install authdrift

Requires semgrep (installed automatically).

Use

authdrift scan ./

Example output:

src/auth/google.ts
   12:18  WARNING  oauth-passport-email-as-primary-key
            This OAuth handler is using `profile.emails[0].value` as a user lookup key.
            When a user renames their Gmail address, this lookup will fail and your
            application will silently create a duplicate user record.
            Fix: use `profile.id` (the OIDC `sub` claim) as the immutable primary key.

JSON output for CI:

authdrift scan ./ --json

Why this matters

Atlassian's own KB confirms that SCIM email changes create duplicate Atlassian Cloud accounts. Google's developer documentation acknowledges that revoke + reauth produces duplicate accounts. The cascade is documented; the fix is not deployed.

authdrift flags the exact code patterns that produce phantom users after a rename event. Three rules, narrowly scoped, designed to slot into CI alongside semgrep, trufflehog, and gitleaks without producing noise.

What it catches today

• Passport.js handlers using profile.emails[0].value as a user lookup key (passport-google-oauth20, passport-google-oauth2)
• NextAuth signIn callbacks resolving users by user.email against Prisma
• Python (Django / SQLAlchemy) handlers querying by userinfo['email'] from Google's userinfo response

What it deliberately does NOT do

• Flag every reference to email in an OAuth file. The rules require the email value to be used as a lookup key, not just read or logged.
• Flag handlers that key on sub / profile.id and use email only as a contact attribute.
• Auto-fix anything. Read-only by design.

Roadmap

• More OAuth library coverage (lucia-auth, authlib, omniauth, Clerk, Supabase Auth, Firebase Auth)
• A --fix mode that suggests the sub-keyed equivalent
• A hosted scan for organisations that can't run a CLI

License

MIT.