Nest has a Fastify URL Encoding Middleware Bypass (TOCTOU)

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

6.9 · 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 · score source

EPSS

• CVE-2025-69211: 0.38% estimated exploitation activity in the next 30 days; percentile 32.27 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

A NestJS application is vulnerable if it meets all of the following criteria: 1. Platform: Uses `@nestjs/platform-fastify`. 2. Security Mechanism: Relies on `NestMiddleware` (via `MiddlewareConsumer`) for security checks (authentication, authorization, etc.), or through `app.use()` 3. Routing: Applies middleware to specific routes using string paths or controllers (e.g., `.forRoutes('admin')`). Example Vulnerable Config: ```ts // app.module.ts export class AppModule implements NestModule { configure(consumer: MiddlewareConsumer) { consumer .apply(AuthMiddleware) // Security check .forRoutes('admin'); // Vulnerable: Path-based restriction } } ``` Attack Vector: - Target Route: `/admin` - Middleware Path: `admin` - Attack Request: `GET /%61dmin` - Result: Middleware is skipped (no match on `%61dmin`), but controller for `/admin` is executed. Consequences: - Authentication Bypass: Unauthenticated users can access protected routes. - Authorization Bypass: Restricted administrative…

Published by the source

30 Dec 2025, 15:32 UTC

Last modified by the source

30 Dec 2025, 15:42 UTC

Source last checked

24 Oct 2026, 22:39 UTC

1. Revision 2 · amended · 24 Oct 2026

   Reviewed OSV alias/range/CVSS4 correction; package source scopes and original publication preserved. No customer finding resolved.

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-8wpr-639p-ccrj

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# Patch Next advisory brief: CVE-2025-69211

Advisory: Nest has a Fastify URL Encoding Middleware Bypass (TOCTOU)
IDs: CVE-2025-69211, GHSA-8wpr-639p-ccrj
Record: https://patchnext.com/advisories/cve-2025-69211 (revision 2, source checked 24 Oct 2026, 22:39 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.9)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: @nestjs/platform-fastify 11.1.11. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm @nestjs/platform-fastify: affected < 11.1.11; fixed in 11.1.11

## Suggested inspection (read-only)
- `npm ls @nestjs/platform-fastify --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on @nestjs/platform-fastify.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-8wpr-639p-ccrj (OSV record GHSA-8wpr-639p-ccrj lists affected ranges: npm @nestjs/platform-fastify >=0 <11.1.11 (fixed))

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