The Python parser is vulnerable to a request smuggling vulnerability due to not parsing trailer sections of an HTTP request.
If a pure Python version of aiohttp is installed (i.e. without the usual C extensions) or AIOHTTP_NO_EXTENSIONS 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/e8d774f635dc6d1cd3174d0e38891da5de0e2b6a
3.12.14Exploitability
AV:NAC:LAT:PPR:NUI:NVulnerable System
VC:NVI:LVA:NSubsequent System
SC:NSI:NSA:N1.7/CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U