Regular expression denial of service in pygments

1) Inefficient regular expression complexity

EUVDB-ID: #VU82226

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-2022-40896

CWE-ID: CWE-1333 - Inefficient Regular Expression Complexity

Exploit availability: No

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 untrusted input with a regular expressions in pygments/lexers/smithy.py. 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

pygments: 2.0 - 2.15.0

CPE2.3

• cpe:2.3:a:pygments:pygments:2.0:*:*:*:*:*:*:*
• cpe:2.3:a:pygments:pygments:2.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:pygments:pygments:2.0.2:*:*:*:*:*:*:*

External links

https://pyup.io/posts/pyup-discovers-redos-vulnerabilities-in-top-python-packages-part-2/
https://github.com/pygments/pygments/blob/master/pygments/lexers/smithy.py#L61

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.