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Vulnerability record · CVE-2021-41817 · published 1 January 2022

CVE-2021-41817: Ruby-lang date inefficient regular expression (redos) vulnerability

Ruby Lang · Date

Date.parse in the date gem through 3.2.0 for Ruby allows ReDoS (regular expression Denial of Service) via a long string. The fixed versions are 3.2.1, 3.1.2, 3.0.2, and 2.0.1.

7.5 CVSS 3.1 High EPSS 3.2% · top 12.2% CWE-1333 · Inefficient regular expression (ReDoS)
7.5CVSS 3.1 base score, v2 5.0
3.2%EPSS exploitation probability, 30 days
NoNot in CISA KEV
9Affected product versions listed by NVD
10References, 2 tagged exploit
17 Jun 2026Last modified by NVD

Description

Date.parse in the date gem through 3.2.0 for Ruby allows ReDoS (regular expression Denial of Service) via a long string. The fixed versions are 3.2.1, 3.1.2, 3.0.2, and 2.0.1.

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

Affected products

9 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://hackerone.com/reports/1254844 Permissions Required
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/IUXQCH6FRKANCVZO2Q7D2SQ
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UTOJGS5IEFDK3UOO7IY4OTT
https://security.gentoo.org/glsa/202401-27
https://www.ruby-lang.org/en/news/2021/11/15/date-parsing-method-regexp-dos-cve-2021-41817/ ExploitVendor Advisory
https://hackerone.com/reports/1254844 Permissions Required
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/IUXQCH6FRKANCVZO2Q7D2SQ
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UTOJGS5IEFDK3UOO7IY4OTT
https://security.gentoo.org/glsa/202401-27
https://www.ruby-lang.org/en/news/2021/11/15/date-parsing-method-regexp-dos-cve-2021-41817/ ExploitVendor Advisory

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Source: NIST National Vulnerability Database (record CVE-2021-41817), CISA KEV, FIRST EPSS (scores of 2026-09-29). This page is refreshed as NVD updates the record.