AIOHTTP: Absolute-form request targets can spoof Request.scheme

Summary

An attacker sending an absolute-form request can spoof the scheme used.

Impact

If user code depends on the Request.scheme attribute for anything security related, an attacker may be able to circumvent this logic, tricking the application into thinking a connection is encrypted when it is not, or vice versa.

Workaround

A WAF rule to reject absolute-form requests (legitimate requests should only use this form for proxies).