Advisory Severity Curation

aiohttp's ClientSession is vulnerable to CRLF injection via version ### Summary Improper validation make it possible for an attacker to modify the HTTP request (e.g. to insert a new header) or even create a new HTTP request if the attacker controls the HTTP version. ### Details The vulnerability only occurs if the attacker can control the HTTP version of the request (including its type). For example if an unvalidated JSON value is used as a version and the attacker is then able to pass an array as the `version` parameter. Furthermore, the vulnerability only occurs when the `Connection` header is passed to the `headers` parameter. At this point, the library will use the parsed value to create the request. If a list is passed, then it bypasses validation and it is possible to perform CRLF injection. ### PoC The POC below shows an example of providing an unvalidated array as a version: https://gist.github.com/jnovikov/184afb593d9c2114d77f508e0ccd508e ### Impact CRLF injection leading to Request Smuggling. ### Workaround If these specific conditions are met and you are unable to upgrade, then validate the user input to the `version` parameter to ensure it is a `str`. Patch: https://github.com/aio-libs/aiohttp/pull/7835/files

aiohttp's ClientSession is vulnerable to CRLF injection via version Improper validation make it possible for an attacker to modify the HTTP request (e.g. to insert a new header) or even create a new HTTP request if the attacker controls the HTTP version.

aiohttp is an asynchronous HTTP client/server framework for asyncio and Python. Improper validation made it possible for an attacker to modify the HTTP request (e.g. to insert a new header) or create a new HTTP request if the attacker controls the HTTP version. The vulnerability only occurs if the attacker can control the HTTP version of the request. This issue has been patched in version 3.9.0.

aiohttp is an asynchronous HTTP client/server framework for asyncio and Python. Improper validation made it possible for an attacker to modify the HTTP request (e.g. to insert a new header) or create a new HTTP request if the attacker controls the HTTP version. The vulnerability only occurs if the attacker can control the HTTP version of the request. This issue has been patched in version 3.9.0.