CVE-2021-23567: The package colors after 1.4.0 are vulnerable to Denial of Service (DoS) that was introduced through an infini

Q: How do I fix CVE-2021-23567?

colors.js: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Q: Is CVE-2021-23567 being exploited?

CVE-2021-23567 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2021-23567 affect?

CVE-2021-23567 affects colors.js. Severity is high (CVSS 7.5). 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

Q: How urgent is CVE-2021-23567?

Priority 56/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

This week

HIGH 7.5REMOTEDOWNGRADE

CVE-2021-23567 is a high-severity flaw (CVSS 7.5) affecting colors.js. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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by a maintainer of colors to make the package unusable, other maintainers' controls over this package appear to have been revoked in an attempt to prevent them from fixing the issue.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++;) { A

Why this priority

High severity
Public exploit reference
Remotely exploitable, no login, no user action

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.7% (top 22%)
CISA exploited list	No
Weakness	CWE-835
Published	2022-01-14
Last modified	2026-06-17

Publisher (CNA): Snyk · Vendor: colors.js project

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2022-01-14 20:15 UTCPublished CVE record published
2026-06-17 03:38 UTCUpdated Record last modified

colors.js project colors.js DOWNGRADE

Affected: 1.4.1 · 1.4.44-liberty-2

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.4.1

1. Check installed version

npm ls colors.js

2. No fixed release: DOWNGRADE to a release before 1.4.1

npm view colors.js versions npm install colors.js@"<1.4.1"

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2021-23567?

colors.js: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2021-23567 being exploited?

CVE-2021-23567 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2021-23567 affect?

CVE-2021-23567 affects colors.js. Severity is high (CVSS 7.5). 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

How urgent is CVE-2021-23567?

Priority 56/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

References

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