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Regular expression denial of service vulnerability (ReDoS) in date

High severity GitHub Reviewed Published Nov 16, 2021 to the GitHub Advisory Database • Updated Jan 24, 2024

Package

bundler date (RubyGems)

Affected versions

>= 3.2.0, < 3.2.1
>= 3.1.0, < 3.1.2
>= 3.0.0, < 3.0.2
< 2.0.1

Patched versions

3.2.1
3.1.2
3.0.2
2.0.1

Description

Date’s parsing methods including Date.parse are using Regexps internally, some of which are vulnerable against regular expression denial of service. Applications and libraries that apply such methods to untrusted input may be affected.

The fix limits the input length up to 128 bytes by default instead of changing the regexps. This is because Date gem uses many Regexps and it is possible that there are still undiscovered vulnerable Regexps. For compatibility, it is allowed to remove the limitation by explicitly passing limit keywords as nil like Date.parse(str, limit: nil), but note that it may take a long time to parse.

Please update the date gem to version 3.2.1, 3.1.2, 3.0.2, and 2.0.1, or later. You can use gem update date to update it. If you are using bundler, please add gem "date", ">= 3.2.1" to your Gemfile. If you import date from the standard library rather than as a gem you should update your Ruby install to 3.0.3, 2.7.5, 2.6.9 or later.

Users unable to upgrade may consider using Date.strptime instead with a predefined date format

Date.strptime('2001-02-20', '%Y-%m-%d')

References

Reviewed Nov 16, 2021
Published to the GitHub Advisory Database Nov 16, 2021
Published by the National Vulnerability Database Jan 1, 2022
Last updated Jan 24, 2024

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS score

0.742%
(81st percentile)

Weaknesses

CVE ID

CVE-2021-41817

GHSA ID

GHSA-qg54-694p-wgpp

Source code

Credits

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