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Moment.js vulnerable to Inefficient Regular Expression Complexity

High severity GitHub Reviewed Published Jul 6, 2022 in moment/moment • Updated Nov 29, 2023

Package

nuget Moment.js (NuGet)

Affected versions

>= 2.18.0, < 2.29.4

Patched versions

2.29.4
npm moment (npm)
>= 2.18.0, < 2.29.4
2.29.4

Description

Impact

  • using string-to-date parsing in moment (more specifically rfc2822 parsing, which is tried by default) has quadratic (N^2) complexity on specific inputs
  • noticeable slowdown is observed with inputs above 10k characters
  • users who pass user-provided strings without sanity length checks to moment constructor are vulnerable to (Re)DoS attacks

Patches

The problem is patched in 2.29.4, the patch can be applied to all affected versions with minimal tweaking.

Workarounds

In general, given the proliferation of ReDoS attacks, it makes sense to limit the length of the user input to something sane, like 200 characters or less. I haven't seen legitimate cases of date-time strings longer than that, so all moment users who do pass a user-originating string to constructor are encouraged to apply such a rudimentary filter, that would help with this but also most future ReDoS vulnerabilities.

References

There is an excellent writeup of the issue here: moment/moment#6015 (comment)

Details

The issue is rooted in the code that removes legacy comments (stuff inside parenthesis) from strings during rfc2822 parsing. moment("(".repeat(500000)) will take a few minutes to process, which is unacceptable.

References

@ichernev ichernev published to moment/moment Jul 6, 2022
Published by the National Vulnerability Database Jul 6, 2022
Published to the GitHub Advisory Database Jul 6, 2022
Reviewed Jul 6, 2022
Last updated Nov 29, 2023

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

0.293%
(69th percentile)

Weaknesses

CVE ID

CVE-2022-31129

GHSA ID

GHSA-wc69-rhjr-hc9g

Source code

Credits

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