CVE-2026-94486: Next Next.js Has Information Disclosure Vulnerability

LOW
Advisory Identifier: GHSA-39w2-rjm5-chcv
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CVSS 5.4
CWE-346
Published
Advisory Summary

CVE-2026-94486 is a LOW (CVSS 5.4) next.js has information disclosure vulnerability (CWE-346: Origin Validation Error) affecting Next libraries in the npm ecosystem. The issue involves next.js has information disclosure in development server's model context protocol endpoint. Remediation is available by upgrading affected packages to version 16.3.8.

CVE-2026-94486 at a Glance

CVE Identifier CVE-2026-94486
GHSA Identifier GHSA-39w2-rjm5-chcv
Severity LOW
CVSS v3.1 Base Score 5.4
CWE Classification CWE-346: Origin Validation Error
Affected Product Next
Package Ecosystem npm
Published Date
Last Updated

Security Impact

CVSS: 5.4

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction Required (UI:R)
Scope Unchanged (S:U)
Confidentiality Low (C:L)
Integrity Low (I:L)
Availability None (A:N)

How to Fix CVE-2026-94486

To remediate this vulnerability, upgrade all affected Next dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

next fixed: 16.3.8 
npm install next@16.3.8
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

npm ls next

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2026-94486, inspect your project dependencies using npm:

npm ls next

Analyze the terminal output to locate any version of Next in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 16.3.8), your application is affected.

Note: The npm ls next command inspects dependencies declared in your package.json and lockfile; it does not perform automated runtime dynamic scanning.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-346: Origin Validation Error, where the product does not properly verify that the source of data or communication is valid. In Next, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

The Next.js development server (`next dev`) exposes a Model Context Protocol endpoint that does not verify which website a request originates from, allowing a malicious website visited by the developer to read sensitive development data — including the project's location on disk, source code snippets from error reports, the route inventory, and development logs. Only applications run with `next dev` are affected. Production deployments do not serve this endpoint.

CVE-2026-94486 Affected Next Versions

1 component(s)
Fixed Versions:
16.3.8
Product / Package Ecosystem Affected Versions Fixed Version
next
npm/next
npm
≥ 16.0.0
< 16.3.8
16.3.8

References

GitHub Advisory / Wiki ADVISORY
https://github.com/vercel/next.js/security/advisories/GHSA-39w2-rjm5-chcv
NVD — CVE-2026-94486 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-94486
Security Fix Commit FIX COMMIT
https://github.com/vercel/next.js/commit/2d9f50a409312696145b82b3157aadb6b1fef476
Next Source Repository REPOSITORY
https://github.com/vercel/next.js
Next Release RELEASE
https://github.com/vercel/next.js/releases/tag/v16.3.8

Frequently Asked Questions

What is CVE-2026-94486?
CVE-2026-94486 is a security vulnerability in Next involving Next.js has information disclosure in development server's Model Context Protocol endpoint under CWE-346: Origin Validation Error.
Which Next versions are affected?
Affected versions include releases prior to 16.3.8 across affected packages: next.
What version fixes CVE-2026-94486?
Upgrading to 16.3.8 (or the latest patched release for your respective branch) resolves the vulnerability.
Is next affected?
Yes, next is affected in releases prior to 16.3.8. Upgrade your dependency to 16.3.8 or later.
What is the CVSS score of CVE-2026-94486?
CVE-2026-94486 has a CVSS v3.1 base score of 5.4 (LOW) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N.
What CWE is associated with CVE-2026-94486?
CVE-2026-94486 is classified under CWE-346: Origin Validation Error (The product does not properly verify that the source of data or communication is valid.).
How can I check npm dependencies for CVE-2026-94486?
Run the dependency tree command: 'npm ls next'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-39w2-rjm5-chcv",
  "modified" : "2026-10-07T20:31:51Z",
  "published" : "2026-10-07T20:31:51Z",
  "aliases" : [ "CVE-2026-94486" ],
  "summary" : "Next.js has information disclosure in development server's Model Context Protocol endpoint",
  "details" : "The Next.js development server (`next dev`) exposes a Model Context Protocol endpoint that does not verify which website a request originates from, allowing a malicious website visited by the developer to read sensitive development data — including the project's location on disk, source code snippets from error reports, the route inventory, and development logs. Only applications run with `next dev` are affected. Production deployments do not serve this endpoint.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "next"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "16.0.0"
      }, {
        "fixed" : "16.3.8"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/vercel/next.js/security/advisories/GHSA-39w2-rjm5-chcv"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-94486"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/vercel/next.js/commit/2d9f50a409312696145b82b3157aadb6b1fef476"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/vercel/next.js"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/vercel/next.js/releases/tag/v16.3.8"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-346" ],
    "severity" : "LOW",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-10-07T20:31:51Z",
    "nvd_published_at" : "2026-10-02T16:16:51Z"
  }
}