The Python HTTP parser may allow a request smuggling attack with the presence of non-ASCII characters.
If a pure Python version of aiohttp is installed (i.e. without the usual C extensions) or AIOHTTPNOEXTENSIONS is enabled, then an attacker may be able to execute a request smuggling attack to bypass certain firewalls or proxy protections.
Patch: https://github.com/aio-libs/aiohttp/commit/32677f2adfd907420c078dda6b79225c6f4ebce0
{
"severity": "LOW",
"github_reviewed_at": "2026-01-05T22:58:57Z",
"cwe_ids": [
"CWE-444"
],
"nvd_published_at": "2026-01-05T23:15:40Z",
"github_reviewed": true
}