CVE-2021-23386: This affects the package dns-packet before 5.2.2

Q: How do I fix CVE-2021-23386?

dns-packet: upgrade to 1.3.4, 5.2.2. Exact commands for each OS are on this page.

Q: Is CVE-2021-23386 being exploited?

CVE-2021-23386 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-2021-23386 affect?

CVE-2021-23386 affects dns-packet. Severity is high (CVSS 7.7). This affects the package dns-packet before 5.2.2. It creates buffers with allocUnsafe and does not always fill them before forming network packets. This can expose internal application memory over unencrypted network when querying crafted i

This month

HIGH 7.7UPGRADE

CVE-2021-23386 is a high-severity flaw (CVSS 7.7) affecting dns-packet. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

This affects the package dns-packet before 5.2.2. It creates buffers with allocUnsafe and does not always fill them before forming network packets. This can expose internal application memory over unencrypted network when querying crafted invalid domain names.

Why this priority

High severity

A fixed release or distro patch exists.

Risk facts

CVSS score	7.7 (High)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	Low
User interaction	None
EPSS exploit chance	1.4% (top 27%)
CISA exploited list	No
Weakness	CWE-909
Published	2021-05-20
Last modified	2026-06-17

Publisher (CNA): Snyk · Vendor: dns-packet project

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

Am I affected?

Timeline

2021-05-20 17:15 UTCPublished CVE record published
2026-06-17 03:38 UTCUpdated Record last modified

dns-packet project dns-packet UPGRADE

Affected: < 1.3.4 · >= 2.0.0 and < 5.2.2

Fixed in: 1.3.4, 5.2.2

Safe to downgrade to: a release before 2.0.0

1. Check installed version

npm ls dns-packet

2. UPGRADE to 1.3.4

npm install dns-packet@">=1.3.4"

3. If no update is available yet, DOWNGRADE to a release before 2.0.0

npm view dns-packet versions npm install dns-packet@"<2.0.0"

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-2021-23386?

dns-packet: upgrade to 1.3.4, 5.2.2. Exact commands for each OS are on this page.

Is CVE-2021-23386 being exploited?

CVE-2021-23386 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-2021-23386 affect?

CVE-2021-23386 affects dns-packet. Severity is high (CVSS 7.7). This affects the package dns-packet before 5.2.2. It creates buffers with allocUnsafe and does not always fill them before forming network packets. This can expose internal application memory over unencrypted network when querying crafted i

How urgent is CVE-2021-23386?

Priority 45/100. High severity

References

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