The HTTP clients in the (1) httplib, (2) urllib, (3) urllib2, and (4) xmlrpclib libraries in CPython (aka Python) 2.x before 2.7.9 and 3.x before 3.4.3, when accessing an HTTPS URL, do not (a) check the certificate against a trust store or verify that the server hostname matches a domain name in the subject's (b) Common Name or (c) subjectAltName field of the X.509 certificate, which allows man-in-the-middle attackers to spoof SSL servers via an arbitrary valid certificate.

Integer overflow in the get_data function in zipimport.c in CPython (aka Python) before 2.7.12, 3.x before 3.4.5, and 3.5.x before 3.5.2 allows remote attackers to have unspecified impact via a negative data size value, which triggers a heap-based buffer overflow.

Multiple integer overflows in Python 2.2.3 through 2.5.1, and 2.6, allow context-dependent attackers to have an unknown impact via a large integer value in the tabsize argument to the expandtabs method, as implemented by (1) the string_expandtabs function in Objects/stringobject.c and (2) the unicode_expandtabs function in Objects/unicodeobject.c. NOTE: this vulnerability reportedly exists because of an incomplete fix for CVE-2008-2315.

An XML External Entity (XXE) issue was discovered in Python through 3.9.1. The plistlib module no longer accepts entity declarations in XML plist files to avoid XML vulnerabilities.

The list_directory function in Lib/SimpleHTTPServer.py in SimpleHTTPServer in Python before 2.5.6c1, 2.6.x before 2.6.7 rc2, and 2.7.x before 2.7.2 does not place a charset parameter in the Content-Type HTTP header, which makes it easier for remote attackers to conduct cross-site scripting (XSS) attacks against Internet Explorer 7 via UTF-7 encoding.

Algorithmic complexity vulnerability in the ssl.match_hostname function in Python 3.2.x, 3.3.x, and earlier, and unspecified versions of python-backports-ssl_match_hostname as used for older Python versions, allows remote attackers to cause a denial of service (CPU consumption) via multiple wildcard characters in the common name in a certificate.

The urllib and urllib2 modules in Python 2.x before 2.7.2 and 3.x before 3.2.1 process Location headers that specify redirection to file: URLs, which makes it easier for remote attackers to obtain sensitive information or cause a denial of service (resource consumption) via a crafted URL, as demonstrated by the file:///etc/passwd and file:///dev/zero URLs.

Python 2.7 before 3.4 only uses the last eight bits of the prefix to randomize hash values, which causes it to compute hash values without restricting the ability to trigger hash collisions predictably and makes it easier for context-dependent attackers to cause a denial of service (CPU consumption) via crafted input to an application that maintains a hash table. NOTE: this vulnerability exists because of an incomplete fix for CVE-2012-1150.

Python Software Foundation CPython version From 3.2 until 3.6.4 on Windows contains a Buffer Overflow vulnerability in os.symlink() function on Windows that can result in Arbitrary code execution, likely escalation of privilege. This attack appears to be exploitable via a python script that creates a symlink with an attacker controlled name or location. This vulnerability appears to have been fixed in 3.7.0 and 3.6.5.

Python before 2.6.8, 2.7.x before 2.7.3, 3.x before 3.1.5, and 3.2.x before 3.2.3 computes hash values without restricting the ability to trigger hash collisions predictably, which allows context-dependent attackers to cause a denial of service (CPU consumption) via crafted input to an application that maintains a hash table.

The CGIHandler class in Python before 2.7.12 does not protect against the HTTP_PROXY variable name clash in a CGI script, which could allow a remote attacker to redirect HTTP requests.

Buffer overflow in the getaddrinfo function in Python 2.2 before 2.2.2, when IPv6 support is disabled, allows remote attackers to execute arbitrary code via an IPv6 address that is obtained using DNS.

An issue was discovered in urllib2 in Python 2.x through 2.7.16 and urllib in Python 3.x through 3.7.3. CRLF injection is possible if the attacker controls a url parameter, as demonstrated by the first argument to urllib.request.urlopen with \r\n (specifically in the path component of a URL that lacks a ? character) followed by an HTTP header or a Redis command. This is similar to the CVE-2019-9740 query string issue. This is fixed in: v2.7.17, v2.7.17rc1, v2.7.18, v2.7.18rc1; v3.5.10, v3.5.10rc1, v3.5.8, v3.5.8rc1, v3.5.8rc2, v3.5.9; v3.6.10, v3.6.10rc1, v3.6.11, v3.6.11rc1, v3.6.12, v3.6.9, v3.6.9rc1; v3.7.4, v3.7.4rc1, v3.7.4rc2, v3.7.5, v3.7.5rc1, v3.7.6, v3.7.6rc1, v3.7.7, v3.7.7rc1, v3.7.8, v3.7.8rc1, v3.7.9.

The audioop module in Python 2.7 and 3.2 does not verify the relationships between size arguments and byte string lengths, which allows context-dependent attackers to cause a denial of service (memory corruption and application crash) via crafted arguments, as demonstrated by a call to audioop.reverse with a one-byte string, a different vulnerability than CVE-2010-1634.

Buffer overflow in the repr function in Python 2.3 through 2.6 before 20060822 allows context-dependent attackers to cause a denial of service and possibly execute arbitrary code via crafted wide character UTF-32/UCS-4 strings to certain scripts.

There is a LOW severity vulnerability affecting CPython, specifically the 'http.cookies' standard library module. When parsing cookies that contained backslashes for quoted characters in the cookie value, the parser would use an algorithm with quadratic complexity, resulting in excess CPU resources being used while parsing the value.

Off-by-one error in the PyLocale_strxfrm function in Modules/_localemodule.c for Python 2.4 and 2.5 causes an incorrect buffer size to be used for the strxfrm function, which allows context-dependent attackers to read portions of memory via unknown manipulations that trigger a buffer over-read due to missing null termination.

A remote code execution vulnerability exists in Visual Studio Code when the Python extension loads workspace settings from a notebook file, aka 'Visual Studio Code Python Extension Remote Code Execution Vulnerability'. This CVE ID is unique from CVE-2020-1171.

The asyncore module in Python before 3.2 does not properly handle unsuccessful calls to the accept function, and does not have accompanying documentation describing how daemon applications should handle unsuccessful calls to the accept function, which makes it easier for remote attackers to conduct denial of service attacks that terminate these applications via network connections.

The is_cgi method in CGIHTTPServer.py in the CGIHTTPServer module in Python 2.5, 2.6, and 3.0 allows remote attackers to read script source code via an HTTP GET request that lacks a / (slash) character at the beginning of the URI.