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MEDIUM severity

GHSA-w37m-7fhw-fmv9 next

MEDIUM

GHSA-w37m-7fhw-fmv9 is a medium-severity (CVSS 5.3) vulnerability in next. A fix is available for next — see the affected versions and patch details below.

Next Server Actions Source Code Exposure

Published
Dec 11, 2025
Updated
Sep 10, 2026
Affected
9 pkgs
Patched
9 / 9
Exploits
None indexed
Exploitation data as of Sep 10, 2026 · OSV.dev, FIRST.org (EPSS)

Real-World Exposure

9 pkgs affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

61Kother npm packages depend on this — each one inherits the vulnerability until it's patched upstream
nextnpm
42.7Mdownloads / week

Description

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.

Affected Packages

9 total 9 fixed
EcosystemPackageVulnerable rangeFix
📦npmnext15.0.0-canary.0&&< 15.0.615.0.6npm install next@15.0.6
📦npmnext15.1.1-canary.0&&< 15.1.1015.1.10npm install next@15.1.10
📦npmnext15.2.0-canary.0&&< 15.2.715.2.7npm install next@15.2.7
📦npmnext15.3.0-canary.0&&< 15.3.715.3.7npm install next@15.3.7
📦npmnext15.4.0-canary.0&&< 15.4.915.4.9npm install next@15.4.9
📦npmnext15.5.1-canary.0&&< 15.5.815.5.8npm install next@15.5.8

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for next, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update next to 15.0.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-w37m-7fhw-fmv9 is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

  4. How O3 protects you

    O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-w37m-7fhw-fmv9 can be triaged on real exposure rather than presence alone.

Tailored to GHSA-w37m-7fhw-fmv9. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

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](https://www.cve.org/CVERecord?id=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](https://react.dev/reference/rsc/server-functions). This could reveal business logic, but would not expose secrets unless they were hardcoded
O3 Security · Impact-Aware SCA

Is GHSA-w37m-7fhw-fmv9 in your dependencies?

O3 Security finds GHSA-w37m-7fhw-fmv9 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

GHSA-w37m-7fhw-fmv9: next (Medium 5.3) | O3 Security