CVE-2019-20477

PyYAML versiones 5.1 hasta 5.1.2, presenta restricciones insuficientes en las funciones load y load_all debido a un problema de deserialización de clase, por ejemplo, Popen es una clase en el módulo subprocess. NOTA: este problema se presenta debido a una corrección incompleta para el CVE-2017-18342.

A vulnerability was discovered in the PyYAML library, where it is susceptible to arbitrary code execution when it processes untrusted YAML files through the full_load method or with the FullLoader loader. Applications that use the library to process untrusted input may be vulnerable to this flaw. An attacker could use this flaw to execute arbitrary code on the system by abusing the python/object/apply constructor.

Python is an interpreted, interactive, object-oriented programming language, which includes modules, classes, exceptions, very high level dynamic data types and dynamic typing. Python supports interfaces to many system calls and libraries, as well as to various windowing systems. Issues addressed include a denial of service vulnerability.