Inefficient Regular Expression Complexity Affecting python27:2.7/python2-pyyaml package, versions <0:3.12-16.module_el8.6.0+2781+fed64c13


Severity

Recommended
medium

Based on AlmaLinux security rating.

Threat Intelligence

EPSS
0.56% (78th percentile)

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  • Snyk IDSNYK-ALMALINUX8-PYTHON27-5635616
  • published28 May 2023
  • disclosed9 Nov 2021

Introduced: 9 Nov 2021

CVE-2021-27291  (opens in a new tab)
CWE-1333  (opens in a new tab)

How to fix?

Upgrade AlmaLinux:8 python27:2.7/python2-pyyaml to version 0:3.12-16.module_el8.6.0+2781+fed64c13 or higher.
This issue was patched in ALSA-2021:4151.

NVD Description

Note: Versions mentioned in the description apply only to the upstream python27:2.7/python2-pyyaml package and not the python27:2.7/python2-pyyaml package as distributed by AlmaLinux. See How to fix? for AlmaLinux:8 relevant fixed versions and status.

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.

CVSS Scores

version 3.1