7.5
HIGH
CVE-2021-27291
Apache Pygments Regular Expression Denial of Service (ReDoS) vulnerability
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.

INFO

Published Date :

March 17, 2021, 1:15 p.m.

Last Modified :

Nov. 7, 2023, 3:31 a.m.

Source :

[email protected]

Remotely Exploitable :

Yes !

Impact Score :

3.6

Exploitability Score :

3.9
Public PoC/Exploit Available at Github

CVE-2021-27291 has a 5 public PoC/Exploit available at Github. Go to the Public Exploits tab to see the list.

Affected Products

The following products are affected by CVE-2021-27291 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Fedoraproject fedora
1 Debian debian_linux
1 Pygments pygments
: Total Affected Vendor : 3 | Products : 3
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2021-27291.

URL Resource
https://gist.github.com/b-c-ds/b1a2cc0c68a35c57188575eb496de5ce Exploit Third Party Advisory
https://github.com/pygments/pygments/commit/2e7e8c4a7b318f4032493773732754e418279a14 Patch Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/03/msg00024.html Mailing List Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/05/msg00003.html Mailing List Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/05/msg00006.html Mailing List Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GSJRFHALQ7E3UV4FFMFU2YQ6LUDHAI55/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WSLD67LFGXOX2K5YNESSWAS4AGZIJTUQ/
https://www.debian.org/security/2021/dsa-4878 Third Party Advisory
https://www.debian.org/security/2021/dsa-4889 Third Party Advisory

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Profile Photo
HotDB-Community/HotDB-Engine

None

CMake Shell Perl C++ C Batchfile CSS Makefile M4 Python

Updated: 6 months, 2 weeks ago
34 stars 0 fork 0 watcher
Born at : Feb. 1, 2024, 11:43 a.m. This repo has been linked 71 different CVEs too.
Profile Photo
retr0-13/regexploit

None

Python JavaScript C#

Updated: 2 years, 5 months ago
0 stars 0 fork 0 watcher
Born at : March 22, 2022, 1:01 p.m. This repo has been linked 11 different CVEs too.
Profile Photo
asa1997/topgear_test

None

Updated: 2 years, 10 months ago
1 stars 1 fork 1 watcher
Born at : July 26, 2021, 8:56 a.m. This repo has been linked 18 different CVEs too.
Profile Photo
engn33r/awesome-redos-security

List of RegEx DoS (ReDoS) CVEs and resources

security awesome redos regex dos regex-dos pentesting awesome-list regex-security

Updated: 2 months, 3 weeks ago
23 stars 2 fork 2 watcher
Born at : June 10, 2021, 1:57 a.m. This repo has been linked 76 different CVEs too.
Profile Photo
doyensec/regexploit

Find regular expressions which are vulnerable to ReDoS (Regular Expression Denial of Service)

Python JavaScript C#

Updated: 2 weeks, 5 days ago
782 stars 50 fork 50 watcher
Born at : Nov. 24, 2020, 7:24 p.m. This repo has been linked 11 different CVEs too.

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2021-27291 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2021-27291 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • CVE Modified by [email protected]

    May. 14, 2024

    Action Type Old Value New Value
  • CVE Modified by [email protected]

    Nov. 07, 2023

    Action Type Old Value New Value
    Added Reference MITRE https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GSJRFHALQ7E3UV4FFMFU2YQ6LUDHAI55/ [No types assigned]
    Added Reference MITRE https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WSLD67LFGXOX2K5YNESSWAS4AGZIJTUQ/ [No types assigned]
    Removed Reference MITRE https://lists.fedoraproject.org/archives/list/[email protected]/message/WSLD67LFGXOX2K5YNESSWAS4AGZIJTUQ/
    Removed Reference MITRE https://lists.fedoraproject.org/archives/list/[email protected]/message/GSJRFHALQ7E3UV4FFMFU2YQ6LUDHAI55/
  • CWE Remap by [email protected]

    Aug. 08, 2023

    Action Type Old Value New Value
    Changed CWE NVD-CWE-Other CWE-1333
  • Modified Analysis by [email protected]

    May. 23, 2022

    Action Type Old Value New Value
    Changed Reference Type https://lists.debian.org/debian-lts-announce/2021/05/msg00003.html No Types Assigned https://lists.debian.org/debian-lts-announce/2021/05/msg00003.html Mailing List, Third Party Advisory
    Changed Reference Type https://lists.debian.org/debian-lts-announce/2021/05/msg00006.html No Types Assigned https://lists.debian.org/debian-lts-announce/2021/05/msg00006.html Mailing List, Third Party Advisory
    Changed Reference Type https://lists.fedoraproject.org/archives/list/[email protected]/message/GSJRFHALQ7E3UV4FFMFU2YQ6LUDHAI55/ No Types Assigned https://lists.fedoraproject.org/archives/list/[email protected]/message/GSJRFHALQ7E3UV4FFMFU2YQ6LUDHAI55/ Mailing List, Third Party Advisory
    Changed Reference Type https://lists.fedoraproject.org/archives/list/[email protected]/message/WSLD67LFGXOX2K5YNESSWAS4AGZIJTUQ/ No Types Assigned https://lists.fedoraproject.org/archives/list/[email protected]/message/WSLD67LFGXOX2K5YNESSWAS4AGZIJTUQ/ Mailing List, Third Party Advisory
    Changed Reference Type https://www.debian.org/security/2021/dsa-4878 No Types Assigned https://www.debian.org/security/2021/dsa-4878 Third Party Advisory
    Changed Reference Type https://www.debian.org/security/2021/dsa-4889 No Types Assigned https://www.debian.org/security/2021/dsa-4889 Third Party Advisory
    Added CPE Configuration OR *cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:* *cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
    Added CPE Configuration OR *cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:* *cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
  • CVE Modified by [email protected]

    May. 06, 2021

    Action Type Old Value New Value
    Added Reference https://lists.debian.org/debian-lts-announce/2021/05/msg00006.html [No Types Assigned]
  • CVE Modified by [email protected]

    May. 06, 2021

    Action Type Old Value New Value
    Added Reference https://lists.fedoraproject.org/archives/list/[email protected]/message/WSLD67LFGXOX2K5YNESSWAS4AGZIJTUQ/ [No Types Assigned]
    Added Reference https://lists.fedoraproject.org/archives/list/[email protected]/message/GSJRFHALQ7E3UV4FFMFU2YQ6LUDHAI55/ [No Types Assigned]
  • CVE Modified by [email protected]

    May. 05, 2021

    Action Type Old Value New Value
    Added Reference https://lists.debian.org/debian-lts-announce/2021/05/msg00003.html [No Types Assigned]
  • CVE Modified by [email protected]

    Apr. 11, 2021

    Action Type Old Value New Value
    Added Reference https://www.debian.org/security/2021/dsa-4889 [No Types Assigned]
  • CVE Modified by [email protected]

    Mar. 30, 2021

    Action Type Old Value New Value
    Added Reference https://www.debian.org/security/2021/dsa-4878 [No Types Assigned]
  • Initial Analysis by [email protected]

    Mar. 24, 2021

    Action Type Old Value New Value
    Added CVSS V2 NIST (AV:N/AC:L/Au:N/C:N/I:N/A:P)
    Added CVSS V3.1 NIST AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
    Changed Reference Type https://gist.github.com/b-c-ds/b1a2cc0c68a35c57188575eb496de5ce No Types Assigned https://gist.github.com/b-c-ds/b1a2cc0c68a35c57188575eb496de5ce Exploit, Third Party Advisory
    Changed Reference Type https://github.com/pygments/pygments/commit/2e7e8c4a7b318f4032493773732754e418279a14 No Types Assigned https://github.com/pygments/pygments/commit/2e7e8c4a7b318f4032493773732754e418279a14 Patch, Third Party Advisory
    Changed Reference Type https://lists.debian.org/debian-lts-announce/2021/03/msg00024.html No Types Assigned https://lists.debian.org/debian-lts-announce/2021/03/msg00024.html Mailing List, Third Party Advisory
    Added CWE NIST NVD-CWE-Other
    Added CPE Configuration OR *cpe:2.3:a:pygments:pygments:*:*:*:*:*:*:*:* versions from (including) 1.1 up to (excluding) 2.7.4
  • CVE Modified by [email protected]

    Mar. 19, 2021

    Action Type Old Value New Value
    Added Reference https://lists.debian.org/debian-lts-announce/2021/03/msg00024.html [No Types Assigned]
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2021-27291 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2021-27291 weaknesses.

Exploit Prediction

EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days.

0.96 }} 0.28%

score

0.81600

percentile

CVSS31 - Vulnerability Scoring System
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality
Integrity
Availability
: