1) Path traversal

Risk: Medium

CVSSv3.1: 6.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C] [PCI]

CVE-ID: CVE-2021-28966

CWE-ID: CWE-22 - Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

Exploit availability: No

Description

The vulnerability allows a remote attacker to perform directory traversal attacks.

The vulnerability exists due to input validation error when processing directory traversal sequences in tmpdir library. A remote attacker can send a specially crafted HTTP request and read arbitrary files on the system.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Ruby: 2.7.0, 2.7.1, 2.7.2, 3.0.0

CPE

• cpe:2.3:a:ruby:ruby:2.7.0:*:*:*:*::*:*
• cpe:2.3:a:ruby:ruby:2.7.1:*:*:*:*::*:*
• cpe:2.3:a:ruby:ruby:2.7.2:*:*:*:*::*:*
• cpe:2.3:a:ruby:ruby:3.0.0:*:*:*:*::*:*

External links

https://www.ruby-lang.org/en/news/2021/04/05/tempfile-path-traversal-on-windows-cve-2021-28966/

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.