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CVE-2021-41817

26
FAUCET Score

CVE-2021-41817 is a Regular Expression Denial of Service (ReDoS) vulnerability affecting the Date.parse function in the Ruby date gem versions through 3.2.0, impacting various Linux distributions like Debian, Fedora, and Red Hat. This vulnerability carries a high CVSS score of 7.5, indicating a severe impact (denial of service) with low attack complexity and no user interaction required. While there is no evidence of active exploitation or publicly available exploit code in Metasploit or ExploitDB, the vulnerability has garnered some community discussion and media coverage, suggesting awareness within the cybersecurity community.

Impacted Technologies

VendorProductVersion(s)CPE
< 2.0.1CPE matchmatch criteria
cpe:2.3:a:ruby-lang:date:*:*:*:*:*:ruby:*:*
>= 3.0.0, < 3.0.2CPE matchmatch criteria
cpe:2.3:a:ruby-lang:date:*:*:*:*:*:ruby:*:*
>= 3.1.0, < 3.1.2CPE matchmatch criteria
cpe:2.3:a:ruby-lang:date:*:*:*:*:*:ruby:*:*
3.2.0CPE matchmatch criteria
cpe:2.3:a:ruby-lang:date:3.2.0:*:*:*:*:ruby:*:*
>= 2.6.0, < 2.6.9CPE matchmatch criteria
cpe:2.3:a:ruby-lang:ruby:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

7.5HIGH

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
3.22%
Probability of exploitation in next 30 days
EPSS Percentile
86.9%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0322 is in the 77th percentile among its peer group of 51,506 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (17)

microsoftpatch availablevia msrc
Product: 19482-16823Fixed in: 3.1.2-2
microsoftpatch availablevia msrc
Product: cbl2 ruby 3.1.2-2 on CBL Mariner 2.0Fixed in: 3.1.2-2
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: ruby:3.0-8060020220810162001.ad008a3a
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8.2 Extended Update SupportFixed in: ruby:2.6-8020020220201131207.4cda2c84
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8.4 Extended Update SupportFixed in: ruby:2.6-8040020220131135901.522a0ee4
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Software Collections for Red Hat Enterprise Linux 7Fixed in: rh-ruby26-ruby-0:2.6.9-120.el7
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Software Collections for Red Hat Enterprise Linux 7Fixed in: rh-ruby30-ruby-0:3.0.4-149.el7
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Software Collections for Red Hat Enterprise Linux 7Fixed in: rh-ruby27-ruby-0:2.7.6-131.el7
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: ruby:2.6-8050020211215144356.c5368500
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: ruby:2.5-8060020220715152618.ad008a3a
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: ruby:2.7-8060020220728151401.ad008a3a
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8.1 Update Services for SAP SolutionsFixed in: ruby:2.6-8010020220201152941.c27ad7f8
View patch
rubygemspatch availablevia ghsa
Product: dateFixed in: 2.0.1
rubygemspatch availablevia ghsa
Product: dateFixed in: 3.0.2
rubygemspatch availablevia ghsa
Product: dateFixed in: 3.2.1
rubygemspatch availablevia ghsa
Product: dateFixed in: 3.1.2
redhatend of lifevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: ruby

Vendor Advisories (3)

microsoft2022-Jan/CVE-2021-41817Important

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.

Jan 11, 2022
rubygemsGHSA-qg54-694p-wgpphigh

Regular expression denial of service vulnerability (ReDoS) in date

Nov 16, 2021
redhatCVE-2021-41817Moderate

ruby: Regular expression denial of service vulnerability of Date parsing methods

Nov 15, 2021

References

hackerone.com / reports/1254844
Permissions Required
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/IUXQCH6FRKANCVZO2Q7D2SQX33FP3KWN
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/UTOJGS5IEFDK3UOO7IY4OTTFGHGLSWZF
security.gentoo.org / glsa/202401-27
ruby-lang.org / en/news/2021/11/15/date-parsing-method-regexp-dos-cve-2021-41817
ExploitVendor Advisory