How severe is CVE-2021-23386?

CVE-2021-23386 has a CVSS score of 6.5/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2021-23386?

CVE-2021-23386 affects the following packages: dns-packet (npm), dns-packet (npm). Ecosystems affected: npm.

How do I fix CVE-2021-23386?

Update dns-packet to version 5.2.2 or later. Run your dependency manager's update command and verify no transitive dependencies pin the vulnerable version. Use O3 Security's SCA scanner to confirm the fix is applied across your entire dependency tree.

Is CVE-2021-23386 actively exploited in the wild?

No public exploit code has been indexed for CVE-2021-23386 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2021-23386?

CVE-2021-23386 has an EPSS (Exploit Prediction Scoring System) score of 0.4%, placing it in the 64th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2021-23386?

CVE-2021-23386 is classified as CWE-909 (CWE-909). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2021-23386 published, and has it been updated?

CVE-2021-23386 was published on May 20, 2021 and was last updated on April 10, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CVE-2021-23386: Potential memory exposure in dns-packet (Medium…

EPSS Exploitation Probability

via FIRST.org ↗

0.4%probability of exploitation in next 30 days

Lower Risk64th percentile0.00%

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

2 pkgs affected

Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.

dns-packetnpm

17.7Mdownloads / week

Description

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.

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`dns-packet`	≥ 2.0.0&&< 5.2.2	5.2.2
📦npm	`dns-packet`	all versions	1.3.2

Frequently Asked Questions

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.

O3 Security · Impact-Aware SCA

Is CVE-2021-23386 in your stack?

O3 detects CVE-2021-23386 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my stack How O3 SCA works