bpo-39603: Prevent http header injection by rejecting control characters in http.client.putrequest(…).
bpo-29778: Ensure python3.dll is loaded from correct locations when Python is embedded (CVE-2020-15523).
bpo-41004: CVE-2020-14422: The __hash__() methods of ipaddress.IPv4Interface and ipaddress.IPv6Interface incorrectly generated constant hash values of 32 and 128 respectively. This resulted in always causing hash collisions. The fix uses hash() to generate hash values for the tuple of (address, mask length, network address).
bpo-39073: Disallow CR or LF in email.headerregistry.Address arguments to guard against header injection attacks.
bpo-38576: Disallow control characters in hostnames in http.client, addressing CVE-2019-18348. Such potentially malicious header injection URLs now cause a InvalidURL to be raised.
bpo-39503: CVE-2020-8492: The AbstractBasicAuthHandler class of the urllib.request module uses an inefficient regular expression which can be exploited by an attacker to cause a denial of service. Fix the regex to prevent the catastrophic backtracking. Vulnerability reported by Ben Caller and Matt Schwager.
bpo-38945: Newline characters have been escaped when performing uu encoding to prevent them from overflowing into to content section of the encoded file. This prevents malicious or accidental modification of data during the decoding process.
bpo-38804: Fixes a ReDoS vulnerability in http.cookiejar. Patch by Ben Caller.
bpo-39017: Avoid infinite loop when reading specially crafted TAR files using the tarfile module (CVE-2019-20907).
bpo-41183: Use 3072 RSA keys and SHA-256 signature for test certs and keys.
bpo-39503: AbstractBasicAuthHandler of urllib.request now parses all WWW-Authenticate HTTP headers and accepts multiple challenges per header: use the realm of the first Basic challenge.