Summary
Moment.js vulnerable to Inefficient Regular Expression Complexity
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.
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
Crafted input forces the application to consume excessive CPU, memory, or other resources, degrading or denying service. Typical impact: denial of service.
CVE-2022-31129 has a CVSS score of 7.5 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (2.29.4); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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The problem is patched in 2.29.4, the patch can be applied to all affected versions with minimal tweaking.
Frequently Asked Questions
- What is CVE-2022-31129? CVE-2022-31129 is a high-severity uncontrolled resource consumption vulnerability in moment (npm), affecting versions >= 2.18.0, < 2.29.4. It is fixed in 2.29.4. Crafted input forces the application to consume excessive CPU, memory, or other resources, degrading or denying service.
- How severe is CVE-2022-31129? CVE-2022-31129 has a CVSS score of 7.5 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which packages are affected by CVE-2022-31129?
moment(npm) (versions >= 2.18.0, < 2.29.4)Moment.js(nuget) (versions >= 2.18.0, < 2.29.4)
- Is there a fix for CVE-2022-31129? Yes. CVE-2022-31129 is fixed in 2.29.4. Upgrade to this version or later.
- Is CVE-2022-31129 exploitable, and should I be worried? Whether CVE-2022-31129 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2022-31129 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2022-31129?
- Upgrade
momentto 2.29.4 or later - Upgrade
Moment.jsto 2.29.4 or later
- Upgrade