CVE-2021-41167: modern-async is an open source JavaScript tooling library for asynchronous operations using async/await and pr

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HIGH 7.5REMOTEUPGRADE

CVE-2021-41167 is a high-severity flaw (CVSS 7.5) affecting modern-async. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

modern-async is an open source JavaScript tooling library for asynchronous operations using async/await and promises. In affected versions a bug affecting two of the functions in this library: forEachSeries and forEachLimit. They should limit the concurrency of some actions but, in practice, they don't. Any code calling these functions will be written thinking they would limit the concurrency but they won't. This could lead to potential security

Why this priority

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

A fixed release or distro patch exists.

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 23%)
CISA exploited list	No
Weakness	CWE-400, CWE-770
Published	2021-10-20
Last modified	2026-06-17

Publisher (CNA): GitHub, Inc. · Vendor: modern-async project

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

Am I affected?

Timeline

2021-10-20 19:15 UTCPublished CVE record published
2026-06-17 04:08 UTCUpdated Record last modified

modern-async project modern-async UPGRADE

Affected: < 1.0.4

Fixed in: 1.0.4

Safe to downgrade to: no unaffected older release

1. Check installed version

npm ls modern-async

2. UPGRADE to 1.0.4

npm install modern-async@">=1.0.4"

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-2021-41167?

modern-async: upgrade to 1.0.4. Exact commands for each OS are on this page.

Is CVE-2021-41167 being exploited?

CVE-2021-41167 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-2021-41167 affect?

CVE-2021-41167 affects modern-async. Severity is high (CVSS 7.5). modern-async is an open source JavaScript tooling library for asynchronous operations using async/await and promises. In affected versions a bug affecting two of the functions in this library: forEachSeries and forEachLimit. They should lim

How urgent is CVE-2021-41167?

Priority 55/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

References

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