sanitizeSameOriginPath returned pathname+search+hash, so a crafted relative next like /..//evil.com passed the origin check but left a //evil.com pathname that re-resolves to a foreign origin when a consumer re-feeds it to new URL(result, base) or router.push. Re-verify the reconstructed path resolves on-origin; reject to / otherwise. Covers the OIDC callback and the password/passkey login redirect.
Adds an OpenID Connect relying-party login path (PKCE authorization-code
flow) against a single env-configured identity provider — additive to
password/passkey login by default, with an operator opt-in (OIDC_ONLY,
enforced server-side on every auth route) to disable them entirely.
First-time sign-in auto-provisions or links an account by verified email.
Closes an open redirect in the post-login `next` parameter (both the new
OIDC path and the pre-existing password/passkey flow shared the same
backslash-normalization bypass) by resolving the target through a real
URL parse and comparing origins instead of a prefix check.
Marc-André Bombeck