CVE-2021-27291

Published: Mar 17, 2021Modified: Jun 17, 2026

7.5

Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Exploitability: 3.9 / Impact: 3.6

Source: NVD

Description

In pygments 1.1+, fixed in 2.7.4, the lexers used to parse programming languages rely heavily on regular expressions. Some of the regular expressions have exponential or cubic worst-case complexity and are vulnerable to ReDoS. By crafting malicious input, an attacker can cause a denial of service.

Affected (5)

Products: Pygments: Pygments · Debian: Debian Linux · Fedoraproject: Fedora

1 product

1 product

1 product

Configuration A

1 vulnerable

Vulnerable Software	Affected Versions
Pygments Pygments	From 1.1 to 2.7.4

Configuration B

2 vulnerable

Vulnerable Software	Affected Versions
Debian Debian Linux	Version 10.0
Debian Debian Linux	Version 9.0

Configuration C

2 vulnerable

Vulnerable Software	Affected Versions
Fedoraproject Fedora	Version 32
Fedoraproject Fedora	Version 33

Related CWEs

Inefficient Regular Expression Complexity

The product uses a regular expression with an inefficient, possibly exponential worst-case computational complexity that consumes excessive CPU cycles.

References (18)

https://gist.github.com/b-c-ds/b1a2cc0c68a35c57188575eb496de5ce

Source: cve@mitre.org

ExploitThird Party Advisory

https://github.com/pygments/pygments/commit/2e7e8c4a7b318f4032493773732754e418279a14

Source: cve@mitre.org

PatchThird Party Advisory

https://lists.debian.org/debian-lts-announce/2021/03/msg00024.html

Source: cve@mitre.org

Mailing ListThird Party Advisory

https://lists.debian.org/debian-lts-announce/2021/05/msg00003.html

Source: cve@mitre.org

Mailing ListThird Party Advisory

https://lists.debian.org/debian-lts-announce/2021/05/msg00006.html

Source: cve@mitre.org

Mailing ListThird Party Advisory

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GSJRFHALQ7E3UV4FFMFU2YQ6LUDHAI55/

Source: cve@mitre.org

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WSLD67LFGXOX2K5YNESSWAS4AGZIJTUQ/

Source: cve@mitre.org

https://www.debian.org/security/2021/dsa-4878

Source: cve@mitre.org

Third Party Advisory

https://www.debian.org/security/2021/dsa-4889

Source: cve@mitre.org

Third Party Advisory

https://gist.github.com/b-c-ds/b1a2cc0c68a35c57188575eb496de5ce

Source: af854a3a-2127-422b-91ae-364da2661108

ExploitThird Party Advisory

https://github.com/pygments/pygments/commit/2e7e8c4a7b318f4032493773732754e418279a14

Source: af854a3a-2127-422b-91ae-364da2661108

PatchThird Party Advisory

https://lists.debian.org/debian-lts-announce/2021/03/msg00024.html

Source: af854a3a-2127-422b-91ae-364da2661108

Mailing ListThird Party Advisory

https://lists.debian.org/debian-lts-announce/2021/05/msg00003.html

Source: af854a3a-2127-422b-91ae-364da2661108

Mailing ListThird Party Advisory

https://lists.debian.org/debian-lts-announce/2021/05/msg00006.html

Source: af854a3a-2127-422b-91ae-364da2661108

Mailing ListThird Party Advisory

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GSJRFHALQ7E3UV4FFMFU2YQ6LUDHAI55/

Source: af854a3a-2127-422b-91ae-364da2661108

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WSLD67LFGXOX2K5YNESSWAS4AGZIJTUQ/

Source: af854a3a-2127-422b-91ae-364da2661108

https://www.debian.org/security/2021/dsa-4878

Source: af854a3a-2127-422b-91ae-364da2661108

Third Party Advisory

https://www.debian.org/security/2021/dsa-4889

Source: af854a3a-2127-422b-91ae-364da2661108

Third Party Advisory

Timeline

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