CVE-2021-27291
python-pygments: ReDoS in multiple lexers
Severity
ModerateRed Hat Product Security
CVSS 3.1
Review impact separately from score.
Published · January 11, 2021
Updated · June 28, 2026
Description
A denial of service attack was discovered against pygments. Some of the regular expressions used to tokenise source code for highlighting have exponential complexity. A specially crafted input file could cause pygments to take effectively infinite time to parse, consuming CPU resources and denying access to the service.
CVSS score applicability
The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.
Mitigation
No mitigation is specified in collected source.
CVSS / CWE
CVSS 3.1 · 7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE-400 · Uncontrolled Resource Consumption