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ModerateVulnerabilityGHSA-w37m-7fhw-fmv9Published 11 Dec 2025

Next Server Actions Source Code Exposure

Affected releases · next

  • 16.x16.0.0 – 16.0.8Fixed in 16.0.9
  • 15.x15.0.0 – 15.5.7Fixed in 15.5.8

On 16.x, the newest line:

npm install next@16.0.9
16.x

  1. Affected

    16.0.0 – 16.0.8

    9 releases

  2. Fixed

    16.0.9 – 16.4.2

    36 releases, latest

15.x

  1. Affected

    15.0.0 – 15.0.5

    6 releases

  2. Fixed

    15.0.6 – 15.1.0

    4 releases

  3. Affected

    15.1.1 – 15.1.9

    9 releases

  4. Fixed

    15.1.10 – 15.1.12

    3 releases

  5. Affected

    15.2.0 – 15.2.6

    7 releases

  6. Fixed

    15.2.7 – 15.2.9

    3 releases

  7. Affected

    15.3.0 – 15.3.6

    7 releases

  8. Fixed

    15.3.7 – 15.3.9

    3 releases

  9. Affected

    15.4.0 – 15.4.8

    9 releases

  10. Fixed

    15.4.9 – 15.5.0

    4 releases

  11. Affected

    15.5.1 – 15.5.7

    7 releases

  12. Fixed

    15.5.8 – 15.5.28

    20 releases

423 stable releases of next, oldest to newest, one row per major.

Is your project affected?

Paste your package.json, or type the range you declare for next. It is read in your browser and sent nowhere.

What happens

A vulnerability affects certain React packages for versions 19.0.0, 19.0.1, 19.1.0, 19.1.1, 19.1.2, 19.2.0, and 19.2.1 and frameworks that use the affected packages, including Next.js 15.x and 16.x using the App Router. The issue is tracked upstream as CVE-2025-55183.

A malicious HTTP request can be crafted and sent to any App Router endpoint that can return the compiled source code of Server Functions. This could reveal business logic, but would not expose secrets unless they were hardcoded directly into Server Function code.