CVE Vulnerabilities

CVE-2021-27291

Inefficient Regular Expression Complexity

Published: Mar 17, 2021 | Modified: Nov 21, 2024
CVSS 3.x
7.5
HIGH
Source:
NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS 2.x
5 MEDIUM
AV:N/AC:L/Au:N/C:N/I:N/A:P
RedHat/V2
RedHat/V3
7.5 MODERATE
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Ubuntu
MEDIUM

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.

Weakness

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

Affected Software

Name Vendor Start Version End Version
Pygments Pygments 1.1 (including) 2.7.4 (excluding)
Eric Ubuntu bionic *
Eric Ubuntu devel *
Eric Ubuntu esm-apps/jammy *
Eric Ubuntu esm-apps/noble *
Eric Ubuntu groovy *
Eric Ubuntu hirsute *
Eric Ubuntu impish *
Eric Ubuntu jammy *
Eric Ubuntu kinetic *
Eric Ubuntu lunar *
Eric Ubuntu mantic *
Eric Ubuntu noble *
Eric Ubuntu oracular *
Eric Ubuntu trusty *
Eric Ubuntu xenial *
Pygments Ubuntu bionic *
Pygments Ubuntu devel *
Pygments Ubuntu focal *
Pygments Ubuntu groovy *
Pygments Ubuntu hirsute *
Pygments Ubuntu impish *
Pygments Ubuntu jammy *
Pygments Ubuntu kinetic *
Pygments Ubuntu lunar *
Pygments Ubuntu mantic *
Pygments Ubuntu noble *
Pygments Ubuntu oracular *
Pygments Ubuntu precise/esm *
Pygments Ubuntu trusty *
Pygments Ubuntu trusty/esm *
Pygments Ubuntu upstream *
Pygments Ubuntu xenial *
Red Hat Automation Hub 4.2 for RHEL 7 RedHat automation-hub-0:4.2.2-1.el7pc *
Red Hat Automation Hub 4.2 for RHEL 7 RedHat python3-django-0:2.2.18-1.el7pc *
Red Hat Automation Hub 4.2 for RHEL 7 RedHat python-bleach-0:3.3.0-1.el7pc *
Red Hat Automation Hub 4.2 for RHEL 7 RedHat python-bleach-allowlist-0:1.0.3-1.el7pc *
Red Hat Automation Hub 4.2 for RHEL 7 RedHat python-galaxy-importer-0:0.2.15-1.el7pc *
Red Hat Automation Hub 4.2 for RHEL 7 RedHat python-galaxy-ng-0:4.2.2-1.el7pc *
Red Hat Automation Hub 4.2 for RHEL 7 RedHat python-pulp-ansible-1:0.5.6-1.el7pc *
Red Hat Automation Hub 4.2 for RHEL 8 RedHat automation-hub-0:4.2.2-1.el8pc *
Red Hat Automation Hub 4.2 for RHEL 8 RedHat python3-django-0:2.2.18-1.el8pc *
Red Hat Automation Hub 4.2 for RHEL 8 RedHat python-bleach-0:3.3.0-1.el8pc *
Red Hat Automation Hub 4.2 for RHEL 8 RedHat python-bleach-allowlist-0:1.0.3-1.el8pc *
Red Hat Automation Hub 4.2 for RHEL 8 RedHat python-galaxy-importer-0:0.2.15-1.el8pc *
Red Hat Automation Hub 4.2 for RHEL 8 RedHat python-galaxy-ng-0:4.2.2-1.el8pc *
Red Hat Automation Hub 4.2 for RHEL 8 RedHat python-pulp-ansible-1:0.5.6-1.el8pc *
Red Hat Enterprise Linux 8 RedHat python36:3.6-8050020210811103506.982725ab *
Red Hat Enterprise Linux 8 RedHat python27:2.7-8050020210811095446.3e7ace8b *
Red Hat Enterprise Linux 8 RedHat resource-agents-0:4.1.1-98.el8 *
Red Hat Software Collections for Red Hat Enterprise Linux 7 RedHat python27-babel-0:0.9.6-10.el7 *
Red Hat Software Collections for Red Hat Enterprise Linux 7 RedHat python27-python-0:2.7.18-3.el7 *
Red Hat Software Collections for Red Hat Enterprise Linux 7 RedHat python27-python-jinja2-0:2.6-16.el7 *
Red Hat Software Collections for Red Hat Enterprise Linux 7 RedHat python27-python-pygments-0:1.5-5.el7 *
Red Hat Software Collections for Red Hat Enterprise Linux 7.7 EUS RedHat python27-babel-0:0.9.6-10.el7 *
Red Hat Software Collections for Red Hat Enterprise Linux 7.7 EUS RedHat python27-python-0:2.7.18-3.el7 *
Red Hat Software Collections for Red Hat Enterprise Linux 7.7 EUS RedHat python27-python-jinja2-0:2.6-16.el7 *
Red Hat Software Collections for Red Hat Enterprise Linux 7.7 EUS RedHat python27-python-pygments-0:1.5-5.el7 *

Extended Description

	  Attackers can create crafted inputs that
	  intentionally cause the regular expression to use
	  excessive backtracking in a way that causes the CPU
	  consumption to spike.

Potential Mitigations

References