fix: remove allowDangerousEmailAccountLinking (pre-registration account linking) - #377
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The flag let a Google sign-in link to a pre-existing credentials account with the same email, so an attacker could POST /api/auth/signup with a victim's email first and have the victim's later Google login link to the attacker-created (attacker-password) row. Drop the flag (defaults to false) so NextAuth won't auto-link across providers by unverified email. Fixes TravellersMeet#370
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This was referenced Aug 10, 2026
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Closes #370
Problem
src/lib/auth.tssetallowDangerousEmailAccountLinking: trueon the Google provider. An attacker couldPOST /api/auth/signupwith a victims email before the victim first uses Google sign-in, creating a credentials user row with the attackers password. When the victim later signs in with Google for that email, the flag links the Google identity to the attacker-created row instead of refusing — the account then carries the attackers credentials alongside the victims OAuth login.Fix
Remove the flag (defaults to
false), so NextAuth will not auto-link a provider to an existing account by (unverified) email.Testing
npx tsc --noEmitclean on the changed file.Contributing as part of Elite Coders Summer of Code (ECSoC 2026).