#VU67555 Incorrect Regular Expression in Mako - CVE-2022-40023

Vulnerability identifier: #VU67555

Vulnerability risk: Medium

CVSSv4.0: 2.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2022-40023

CWE-ID: CWE-185

Exploitation vector: Network

Exploit availability: No

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

Vendor: SQLAlchemy

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 within the Lexer class. A remote attacker can pass specially crafted data to the application and perform regular expression denial of service (ReDos) attack.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Mako: 0.1.0 - 1.2.1

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External links
https://github.com/sqlalchemy/mako/commit/925760291d6efec64fda6e9dd1fd9cfbd5be068c
https://pyup.io/vulnerabilities/CVE-2022-40023/50870/
https://github.com/sqlalchemy/mako/issues/366
https://github.com/sqlalchemy/mako/blob/c2f392e0be52dc67d1b9770ab8cce6a9c736d547/mako/ext/extract.py#L21

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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.