The smtplib library in CPython (aka Python) before 2.7.12, 3.x before 3.4.5, and 3.5.x before 3.5.2 does not return an error when StartTLS fails, which might allow man-in-the-middle attackers to bypass the TLS protections by leveraging a network position between the client and the registry to block the StartTLS command, aka a "StartTLS stripping attack."
The overflow protection in Expat is removed by compilers with certain optimization settings, which allows remote attackers to cause a denial of service (crash) or possibly execute arbitrary code via crafted XML data. NOTE: this vulnerability exists because of an incomplete fix for CVE-2015-1283 and CVE-2015-2716.
Expat allows context-dependent attackers to cause a denial of service (crash) or possibly execute arbitrary code via a malformed input document, which triggers a buffer overflow.
Untrusted search path vulnerability in python.exe in Python through 3.5.0 on Windows allows local users to gain privileges via a Trojan horse readline.pyd file in the current working directory. NOTE: the vendor says "It was determined that this is a longtime behavior of Python that cannot really be altered at this point."
Multiple integer overflows in the XML_GetBuffer function in Expat through 2.1.0, as used in Google Chrome before 44.0.2403.89 and other products, allow remote attackers to cause a denial of service (heap-based buffer overflow) or possibly have unspecified other impact via crafted XML data, a related issue to CVE-2015-2716.
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.
Race condition in the _get_masked_mode function in Lib/os.py in Python 3.2 through 3.5, when exist_ok is set to true and multiple threads are used, might allow local users to bypass intended file permissions by leveraging a separate application vulnerability before the umask has been set to the expected value.
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.
The updatePosition function in lib/xmltok_impl.c in libexpat in Expat 2.0.1, as used in Python, PyXML, w3c-libwww, and other software, allows context-dependent attackers to cause a denial of service (application crash) via an XML document with crafted UTF-8 sequences that trigger a buffer over-read, a different vulnerability than CVE-2009-2625.
The pygresql module 3.8.1 and 4.0 for Python does not properly support the PQescapeStringConn function, which might allow remote attackers to leverage escaping issues involving multibyte character encodings.