CVE-2021-3842

Name: CVE-2021-3842
Creator: NVD / NIST
Published: 2022-01-04T15:15:07.833+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 1.50%

Last modified Jun 17, 2026

CVE-2021-3842 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. nltk is vulnerable to Inefficient Regular Expression Complexity. EPSS estimates a 1.50% chance of exploitation in the next 30 days.

Description

nltk is vulnerable to Inefficient Regular Expression Complexity

Metrics

CVSS 3.1

7.5/10

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

EPSS Probability

1.50%

71.1th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-1333

Affected Software

Vendor	Product	Versions
Nltk	Nltk	< 3.6.6
Debian	Debian Linux	9.0
Debian	Debian Linux	10.0
Debian	Debian Linux	11.0
Fedoraproject	Fedora	35

References

https://github.com/nltk/nltk/commit/2a50a3edc9d35f57ae42a921c621edc160877f4dPatch, Third Party Advisory
https://huntr.dev/bounties/761a761e-2be2-430a-8d92-6f74ffe9866aExploit, Issue Tracking, Patch, Third Party Advisory
https://github.com/nltk/nltk/commit/2a50a3edc9d35f57ae42a921c621edc160877f4dPatch, Third Party Advisory
https://huntr.dev/bounties/761a761e-2be2-430a-8d92-6f74ffe9866aExploit, Issue Tracking, Patch, Third Party Advisory

Timeline

Published: Jan 4, 2022
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-3842?

nltk is vulnerable to Inefficient Regular Expression Complexity

How severe is CVE-2021-3842?

CVE-2021-3842 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 1.50% probability of exploitation in the next 30 days.

How do I fix CVE-2021-3842?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-3842?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST