A vulnerability was found in Python 2.7.x through 2.7.16 and 3.x through 3.7.2. An improper Handling of Unicode Encoding (with an incorrect netloc) during NFKC normalization could lead to an Information Disclosure (credentials, cookies, etc. that are cached against a given hostname) in the urllib.parse.urlsplit, urllib.parse.urlparse components. A specially crafted URL could be incorrectly parsed to locate cookies or authentication data and send that information to a different host than when parsed correctly.

References: https://bugs.python.org/issue36216 https://python-security.readthedocs.io/vuln/urlsplit-nfkc-normalization.html

Uptream Patch: https://github.com/python/cpython/pull/12201