GHSA-wc69-rhjr-hc9g
HIGHMoment.js vulnerable to Inefficient Regular Expression Complexity
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
moment.NETMoment.jsReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects npm, NuGet packages — download data is not available via public APIs for these ecosystems.
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: 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 Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | moment | ≥ 2.18.0&&< 2.29.4 | 2.29.4 |
| .NETNuGet | Moment.js | ≥ 2.18.0&&< 2.29.4 | 2.29.4 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for moment. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update moment to 2.29.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-wc69-rhjr-hc9g is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-wc69-rhjr-hc9g is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-wc69-rhjr-hc9g. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-wc69-rhjr-hc9g in your dependencies?
O3 detects GHSA-wc69-rhjr-hc9g across npm, NuGet dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.