High

Moment.js vulnerable to Inefficient Regular Expression Complexity

  • Disclosed: 06.07.2022
  • Updated: 11.10.2026 11:23

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: https://github.com/moment/moment/pull/6015#issuecomment-1152961973=

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.

Affected software

Click a technology to see all vulnerabilities affecting it.

PlatformPackageVulnerable versionsFixed in
npm package moment >= 2.18.0, < 2.29.4 2.29.4
.NET (NuGet) Moment.js >= 2.18.0, < 2.29.4 2.29.4

References

CVSS score 7.5/10
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE)
CWE-1333, CWE-400
Platform
npm, .NET (NuGet)
Package
moment, Moment.js
Disclosed
06.07.2022
Updated
11.10.2026 11:23

Sources and licenses

OSV / GitHub Advisory Database - GHSA-wc69-rhjr-hc9g - CC BY 4.0

Vulnerability history: Moment.js

All published vulnerabilities of this package (.NET (NuGet)), newest first. Shows whether this is a one-off slip or a package that needs watching.

Total entries
2
First → latest
04.2022 07.2022
Without a fix
0
Exploited in attacks
0

Severity breakdown

  • High 2

Disclosures per year

  1. 2022: 2
  2. 2023: 0
  3. 2024: 0
  4. 2025: 0
  5. 2026: 0
  1. Moment.js vulnerable to Inefficient Regular Expression Complexity this entry
    High · 7.5 CVE-2022-31129 >= 2.18.0, < 2.29.4 2.29.4
  2. High · 7.5 CVE-2022-24785 < 2.29.2 2.29.2

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