Improper Access Control in PyYAML component for Python

1) Improper access control

EUVDB-ID: #VU25542

Risk: High

CVSSv3.1: 8.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2019-20477

CWE-ID: CWE-284 - Improper Access Control

Exploit availability: No

Description

The vulnerability allows a remote attacker to gain unauthorized access to otherwise restricted functionality.

The vulnerability exists due to improper access restrictions in the "load" and "load_all" functions. A remote attacker can bypass implemented security restrictions and gain unauthorized access to the application.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

PyYAML: 5.1

External links

http://github.com/yaml/pyyaml/blob/master/CHANGES
http://www.exploit-db.com/download/47655
http://github.com/yaml/pyyaml/issues/265

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.