USN-5200-1

It was discovered that the urllib.request.AbstractBasicAuthHandler class in Python contains regex allowing for catastrophic backtracking. Specially crafted traffic from a malicious HTTP server could cause a regular expression denial of service (ReDoS) condition for a client. (CVE-2020-8492)

It was discovered that the urllib.request.AbstractBasicAuthHandler class in Python contains regex with a quadratic worst-case time complexity. Specially crafted traffic from a malicious HTTP server could cause a regular expression denial of service (ReDoS) condition for a client. (CVE-2021-3733)

It was discovered that the Python urllib http client could enter into an infinite loop when incorrectly handling certain server responses (100 Continue response). Specially crafted traffic from a malicious HTTP server could cause a denial of service (DoS) condition for a client. (CVE-2021-3737)