CVE-2026-34520: AIOHTTP: C parser (llhttp) accepts null bytes and control characters in response header values - header injection / security bypass

### Summary The C parser (the default for most installs) accepted null bytes and control characters is response headers. ### Impact An attacker could send header values that are interpreted differently than expected due to the presence of control characters. For example, `request.url.origin()` may return a different value than the raw Host header, or what a reverse proxy interpreted it as., potentially resulting in some kind of security bypass. ----- Patch: https://github.com/aio-libs/aiohttp/commit/9370b9714a7a56003cacd31a9b4ae16eab109ba4