WP Limit Login Attempts <= 2.6.4 - IP Spoofing

The plugin prioritizes getting a visitor's IP from certain HTTP headers over PHP's REMOTEADDR, which makes it possible to bypass IP-based restrictions on login forms. Set HTTPCLIENTIP or HTTPXFORWARDEDFOR as used in wplimitgetip to spoof the IP address and bypass the block...

Login Block IPs <= 1.0.0 - IP Spoofing Bypass

The function checkisloginpage uses headers for the IP check, which can be easily spoofed. Set HTTPCLIENTIP to bypass blocks / use allowed IP addresses...