#VU59824 Incorrect Regular Expression in Date - CVE-2021-41817

Vulnerability identifier: #VU59824

Vulnerability risk: Medium

CVSSv4.0: 6.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2021-41817

CWE-ID: CWE-185

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Date
Web applications / Modules and components for CMS

Vendor: Ruby

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to insufficient input validation when processing regular expressions on date parsing methods. A remote attacker can pass specially crafted data to the application and perform regular expression denial of service (ReDos) attack.

Mitigation
Cybersecurity Help is currently unaware of any official solution to address this vulnerability..

Vulnerable software versions

Date: 2.0.0 - 3.2.0

---

External links
https://hackerone.com/reports/1254844
https://www.ruby-lang.org/en/news/2021/11/15/date-parsing-method-regexp-dos-cve-2021-41817/

---

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.