CVE-2021-23567 is a high-severity (CVSS 7.5) CWE-835 vulnerability in colors. 4 public exploit references exist, so weaponization risk is real. No vendor fix is recorded yet; mitigation options are listed below.
Infinite Loop in colors.js
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2021-23567 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 385,987 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
colorsnpmDescription
The package colors after 1.4.0 are vulnerable to Denial of Service (DoS) that was introduced through an infinite loop in the americanFlag module. Unfortunately this appears to have been a purposeful attempt by a maintainer of colors to make the package unusable, other maintainers' controls over this package appear to have been revoked in an attempt to prevent them from fixing the issue. Vulnerable Code js for (let i = 666; i < Infinity; i++;) { Alternative Remediation Suggested * Pin dependancy to 1.4.0
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | colors | ≥ 1.4.1 | No fix |
Affected Products
colors.jscolors.js_projectResearch use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
The package colors after 1.4.0 are vulnerable to Denial of Service (DoS)…
The package colors after 1.4.0 are vulnerable to Denial of Service (DoS)…
The package colors after 1.4.0 are vulnerable to Denial of Service (DoS)…
The package colors after 1.4.0 are vulnerable to Denial of Service (DoS)…
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for colors, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Remediation status
No patched version of colors has shipped for CVE-2021-23567 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.
Frequently Asked Questions
Is CVE-2021-23567 in your dependencies?
Find it across npm, including transitive dependencies.