AIOHTTP vulnerable to brute-force leak of internal static file path components

Summary

Path normalization for static files prevents path traversal, but opens up the ability for an attacker to ascertain the existence of absolute path components.

Impact

If an application uses web.static() (not recommended for production deployments), it may be possible for an attacker to ascertain the existence of path components.

Patch: https://github.com/aio-libs/aiohttp/commit/f2a86fd5ac0383000d1715afddfa704413f0711e