Affected: twisted treq

treq is an HTTP library inspired by requests but written on top of Twisted's Agents. Treq's request methods (`treq.get`, `treq.post`, etc.) and `treq.client.HTTPClient` constructor accept cookies as a dictionary. Such cookies are not bound to a single domain, and are therefore sent to *every* domain ("supercookies"). This can potentially cause sensitive information to leak upon an HTTP redirect to a different domain., e.g. should `https://example.com` redirect to `http://cloudstorageprovider.com` the latter will receive the cookie `session`. Treq 2021.1.0 and later bind cookies given to request methods (`treq.request`, `treq.get`, `HTTPClient.request`, `HTTPClient.get`, etc.) to the origin of the *url* parameter. Users are advised to upgrade. For users unable to upgrade Instead of passing a dictionary as the *cookies* argument, pass a `http.cookiejar.CookieJar` instance with properly domain- and scheme-scoped cookies in it.

Affected: PyPI: treq

### Impact

Treq's request methods (`treq.get`, `treq.post`, `HTTPClient.request`, `HTTPClient.get`, etc.) accept cookies as a dictionary, for example:

```py treq.get('https://example.com/', cookies={'session': '1234'}) ```

Such cookies are not bound to a single domain, and are therefore sent to *every* domain ("supercookies"). This can potentially cause sensitive information to leak upon an HTTP redirect to a different domain., e.g. should `https://example.com` redirect to `http://cloudstorageprovider.com` the latter will receive the cookie `session`.

### Patches

Treq 2021.1.0 and later bind cookies given to request methods (`treq.request`, `treq.get`, `HTTPClient.request`, `HTTPClient.get`, etc.) to the origin of the *url* parameter.

### Workarounds

Instead of passing a dictionary as the *cookies* argument, pass a `http.cookiejar.CookieJar` instance with properly domain- and scheme-scoped cookies in it:

```py from http.cookiejar import CookieJar from requests.cookies import create_cookie

jar = CookieJar() jar.add_cookie( create_cookie( name='session', value='1234', domain='example.com', secure=True, ), ) client = HTTPClient(cookies=jar) client.get('https://example.com/') ```

### References

* Originally reported at [huntr.dev](https://huntr.dev/bounties/3c9204fc-a3d1-4441-8599-924c5f57e7ae/?token=06d930e37046c914bcb037e85cc227dc7b510b475989fc69837566562ba899277d46b0fb4b1e21cdcb6ddc1b7d9b1ded632cf3a3551ecb89afca16a63b34641284…