CVE-2026-71250 Firefly III - Webhook URL Validation Explicitly Allows Loopback and Is Bypassable via DNS Rebinding

Firefly III's webhook URL validator IsValidWebhookUrl.php filters most private/reserved IPv4 ranges but contains an explicit early-return that allows any resolved address in 127.0.0.0/8, permitting an authenticated user with webhooks enabled, which is off by default to configure a webhook targeti...