prevent deployments of Next.js apps vulnerable to CVE-2025-66478

[leoortizz]

Description

This PR blocks the deployment of Next.js applications that are vulnerable to CVE-2025-66478 (Remote Code Execution in React Server Components).

Affected deployments are those using:

1. Next.js App Router (/app directory)
2. Server-side features requiring a backend (Cloud Functions)
3. Vulnerable Next.js versions:
   • 15.x: < 15.0.5, < 15.1.9, < 15.2.6, < 15.3.6, < 15.4.8, < 15.5.7
   • 16.x: < 16.0.7
   • 14.x: Canary releases >= 14.3.0-canary.77

Changes:

• Added isNextJsVersionVulnerable utility in src/frameworks/next/utils.ts to check against the specific vulnerable semver ranges.
• Updated src/frameworks/next/index.ts to throw a FirebaseError during the build step if a vulnerable version is detected when wantsBackend is true.
• Added comprehensive unit tests in src/frameworks/next/utils.spec.ts.

Scenarios Tested

• Unit Tests: Verified isNextJsVersionVulnerable against a matrix of versions:
  • Blocked: 15.0.0, 15.1.0, 15.4.7, 16.0.6, 14.3.0-canary.77.
  • Allowed (Patched): 15.0.5, 15.1.9, 16.0.7.
  • Allowed (Future): Verified that future minor versions (e.g., 15.6.0) are treated as safe/patched.
  • Allowed (Stable/Legacy): Stable 14.x and older versions (13.x) are not blocked.

Sample Commands

This change affects firebase deploy behavior for Next.js projects.

# If using a vulnerable version (e.g. 16.0.0):
$ firebase deploy

...

Error: Next.js version 16.0.0 is vulnerable to CVE-2025-66478.
Please upgrade to a patched version: 16.0.7+.
See https://nextjs.org/blog/CVE-2025-66478 for more details.

[gemini-code-assist]

Summary of Changes

Hello @leoortizz, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This change enhances the security posture of Next.js application deployments by integrating a proactive check against a known vulnerability (CVE-2025-66478). It ensures that applications using the App Directory and requiring backend services are not deployed if they are running an unpatched Next.js version, thereby protecting users from potential security risks. The implementation provides clear feedback and actionable steps for developers to resolve the issue.

Highlights

• Security Vulnerability Prevention: This pull request introduces a critical security measure to prevent the deployment of Next.js applications that are vulnerable to CVE-2025-66478.
• Deployment Blocking Logic: During the build process, if a Next.js application uses the App Directory, requires a backend, and is detected to be running a vulnerable version of Next.js, the deployment will now be blocked with a FirebaseError.
• Version Detection and Validation: New utility functions have been added to accurately retrieve the raw Next.js version and to determine if that version falls within the known vulnerable ranges for CVE-2025-66478, including specific patch levels for various minor versions and canary releases.
• User Guidance: The error message provided when a vulnerable version is detected includes clear instructions for users to upgrade to a patched version or downgrade to a stable Next.js 14.x release, along with a link to the official Next.js blog post for more details.

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[gemini-code-assist]

Code Review

This pull request introduces a critical security check for Next.js applications, preventing deployments of versions vulnerable to CVE-2025-66478. The changes include adding utility functions to detect vulnerable Next.js versions and integrating this check into the build process. Tests for the new utility functions have also been added, ensuring the logic for version detection is robust. The overall approach is sound and addresses a significant security concern.