Cross-site scripting in Python - CVE-2019-16935

Detailed vulnerability description

The vulnerability allows a remote attacker to perform cross-site scripting (XSS) attacks.

The vulnerability exists due to insufficient sanitization of user-supplied data when processing the server_title field in the XML-RPC server (Lib/DocXMLRPCServer.py) in Python 2.x, and in Lib/xmlrpc/server.py in Python 3.x. A remote attacker can trick the victim to follow a specially crafted link and execute arbitrary HTML and script code in user's browser in context of vulnerable website.

Successful exploitation of this vulnerability may allow a remote attacker to steal potentially sensitive information, change appearance of the web page, perform phishing and drive-by-download attacks.

How to mitigate CVE-2019-16935

Sources

• https://bugs.python.org/issue38243
• https://github.com/python/cpython/blob/35c0809158be7feae4c4f877a08b93baea2d8291/Lib/xmlrpc/server.py#L897
• https://github.com/python/cpython/blob/e007860b8b3609ce0bc62b1780efaa06241520bd/Lib/DocXMLRPCServer.py#L213
• https://github.com/python/cpython/pull/16373