CVE-2019-20478

A vulnerability was discovered in the ruamel.yaml library, where it is susceptible to arbitrary code execution when it processes untrusted YAML files through the load() method. Applications that use ruamel.yaml 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.

Mitigation

Use the 'safe_load' method in place of 'load' if loading untrusted data. Alternatively use:
yaml=YAML(typ='safe')
yaml.load()

Reference: <https://yaml.readthedocs.io/en/latest/basicuse.html&gt;