Alex Gaynor reports:
""" When Python's standard library HTTP clients (httplib, urllib, urllib2, xmlrpclib) are used to access resources with HTTPS, by default the certificate is not checked against any trust store, nor is the hostname in the certificate checked against the requested host. It was possible to configure a trust root to be checked against, however there were no faculties for hostname checking.
This made MITM attacks against the HTTP clients trivial, and violated RFC 2818 (http://tools.ietf.org/html/rfc2818#section-3).
Python 2.7.9 has been issued to resolve this issue. It is also resolved in 3.4.3, which has not yet been released. """
CVE request: http://seclists.org/oss-sec/2014/q4/1022
A flaw was found in the way the DES/3DES cipher was used as part of the TLS/SSL protocol. A man-in-the-middle attacker could use this flaw to recover some plaintext data by capturing large amounts of encrypted traffic between TLS/SSL server and client if the communication used a DES/3DES based ciphersuite.
An out-of-bounds read flaw was found in the way Expat processed certain input. A remote attacker could send specially crafted XML that, when parsed by an application using the Expat library, would cause that application to crash or, possibly, execute arbitrary code with the permission of the user running the application.
It was found that OpenSSL was vulnerable to a SSL/TLS MITM vulnerability. An attacker using a carefully crafted handshake can force the use of weak keying material in OpenSSL SSL/TLS clients and servers. This can be exploited by a Man-in-the-middle (MITM) attack where the attacker can decrypt and modify traffic from the attacked client and server.
As per the upstream advisory:
The attack can only be performed between a vulnerable client and server. OpenSSL clients are vulnerable in all versions of OpenSSL. Servers are only known to be vulnerable in OpenSSL 1.0.1 and 1.0.2-beta1. Users of OpenSSL servers earlier than 1.0.1 are advised to upgrade as a precaution.
OpenSSL 0.9.8 SSL/TLS users (client and/or server) should upgrade to 0.9.8za. OpenSSL 1.0.0 SSL/TLS users (client and/or server) should upgrade to 1.0.0m. OpenSSL 1.0.1 SSL/TLS users (client and/or server) should upgrade to 1.0.1h.
Acknowledgements:
Red Hat would like to thank the OpenSSL project for reporting this issue. Upstream acknowledges KIKUCHI Masashi of Lepidum as the original reporter of this issue.
Array index error in the scanstring function in the json module in Python 2.7 through 3.5 and simplejson before 2.6.1 allows context-dependent attackers to read arbitrary process memory via a negative index value in the idx argument to the rawdecode function.
Last updated 15 January 2025
A null pointer dereference vulnerability was found in the certificate parsing code in Python. This causes a denial of service to applications when parsing specially crafted certificates. This vulnerability is unlikely to be triggered if application enables SSL/TLS certificate validation and accepts certificates only from trusted root certificate authorities.
An issue was discovered in Python through 2.7.16, 3.x through 3.5.7, 3.6.x through 3.6.9, and 3.7.x through 3.7.4. The email module wrongly parses email addresses that contain multiple @ characters. An application that uses the email module and implements some kind of checks on the From/To headers of a message could be tricked into accepting an email address that should be denied. An attack may be the same as in CVE-2019-11340; however, this CVE applies to Python more generally.
Last updated 25 August 2025
A flaw was found in python's elementtree.c module, a wrapper for libexpat XML parser. xml.etree C accelerator don't call XMLSetHashSalt(), failing to properly initiate the random hash seed from a good CSPRNG source and making hash collision attacks with carefully crafted XML data easier.
Upstream bug:
https://bugs.python.org/issue34623.
libexpat. Multiple issues were addressed by updating to version 2.2.1