It was discovered that pip did not properly sanitize the filename during pip install. A remote attacker could possible use this issue to read and write arbitrary files on the host filesystem as root, resulting in a directory traversal attack (CVE-2019-20916).
urllib3 before 1.25.9 allows CRLF injection if the attacker controls the HTTP request method, as demonstrated by inserting CR and LF control characters in the first argument of putrequest(). The python-pip package bundles a copy of python-urllib3, which was affected by this issue. The bundled copy was patched to fix the issue (CVE-2020-26137).