CVE-2026-27978: Next Null Origin Can Bypass Server Vulnerability

MODERATE
Advisory Identifier: GHSA-mq59-m269-xvcx
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CWE-352
Published
Advisory Summary

CVE-2026-27978 is a MODERATE null origin can bypass server vulnerability (CWE-352: Cross-Site Request Forgery (CSRF)) affecting Next libraries in the npm ecosystem. The issue involves null origin can bypass server actions csrf checks. Remediation is available by upgrading affected packages to version 16.1.7.

CVE-2026-27978 at a Glance

CVE Identifier CVE-2026-27978
GHSA Identifier GHSA-mq59-m269-xvcx
Severity MODERATE
CVSS v3.1 Base Score N/A
CWE Classification CWE-352: Cross-Site Request Forgery (CSRF)
Affected Product Next
Package Ecosystem npm
Published Date
Last Updated

How to Fix CVE-2026-27978

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: 16.1.7 
npm install next@16.1.7
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-2026-27978, 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 16.1.7), 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-352: Cross-Site Request Forgery (CSRF), where the web application does not, or cannot, sufficiently verify whether a request was intentionally provided by the user who sent the request, which could have originated from an unauthorized actor. 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

## Summary `origin: null` was treated as a "missing" origin during Server Action CSRF validation. As a result, requests from opaque contexts (such as sandboxed iframes) could bypass origin verification instead of being validated as cross-origin requests. ## Impact An attacker could induce a victim browser to submit Server Actions from a sandboxed context, potentially executing state-changing actions with victim credentials (CSRF). ## Patches Fixed by treating `'null'` as an explicit origin value and enforcing host/origin checks unless `'null'` is explicitly allowlisted in `experimental.serverActions.allowedOrigins`. ## Workarounds If upgrade is not immediately possible: - Add CSRF tokens for sensitive Server Actions. - Prefer `SameSite=Strict` on sensitive auth cookies. - Do not allow `'null'` in `serverActions.allowedOrigins` unless intentionally required and additionally protected.

CVE-2026-27978 Affected Next Versions

1 component(s)
Fixed Versions:
16.1.7
Product / Package Ecosystem Affected Versions Fixed Version
next
npm/next
npm
≥ 16.0.1
< 16.1.7
16.1.7

References

GitHub Advisory / Wiki ADVISORY
https://github.com/vercel/next.js/security/advisories/GHSA-mq59-m269-xvcx
NVD — CVE-2026-27978 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-27978
Security Fix Commit FIX COMMIT
https://github.com/vercel/next.js/commit/a27a11d78e748a8c7ccfd14b7759ad2b9bf097d8
Next Source Repository REPOSITORY
https://github.com/vercel/next.js
Next Release RELEASE
https://github.com/vercel/next.js/releases/tag/v16.1.7

Frequently Asked Questions

What is CVE-2026-27978?
CVE-2026-27978 is a security vulnerability in Next involving null origin can bypass Server Actions CSRF checks under CWE-352: Cross-Site Request Forgery (CSRF).
Which Next versions are affected?
Affected versions include releases prior to 16.1.7 across affected packages: next.
What version fixes CVE-2026-27978?
Upgrading to 16.1.7 (or the latest patched release for your respective branch) resolves the vulnerability.
Is next affected?
Yes, next is affected in releases prior to 16.1.7. Upgrade your dependency to 16.1.7 or later.
What CWE is associated with CVE-2026-27978?
CVE-2026-27978 is classified under CWE-352: Cross-Site Request Forgery (CSRF) (The web application does not, or cannot, sufficiently verify whether a request was intentionally provided by the user who sent the request, which could have originated from an unauthorized actor.).
How can I check npm dependencies for CVE-2026-27978?
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-mq59-m269-xvcx",
  "modified" : "2026-03-19T18:28:49Z",
  "published" : "2026-03-17T15:30:14Z",
  "aliases" : [ "CVE-2026-27978" ],
  "summary" : "Next.js: null origin can bypass Server Actions CSRF checks",
  "details" : "## Summary\n`origin: null` was treated as a \"missing\" origin during Server Action CSRF validation. As a result, requests from opaque contexts (such as sandboxed iframes) could bypass origin verification instead of being validated as cross-origin requests.\n\n## Impact\nAn attacker could induce a victim browser to submit Server Actions from a sandboxed context, potentially executing state-changing actions with victim credentials (CSRF).\n\n## Patches\nFixed by treating `'null'` as an explicit origin value and enforcing host/origin checks unless `'null'` is explicitly allowlisted in `experimental.serverActions.allowedOrigins`.  \n\n## Workarounds\nIf upgrade is not immediately possible:\n- Add CSRF tokens for sensitive Server Actions.\n- Prefer `SameSite=Strict` on sensitive auth cookies.\n- Do not allow `'null'` in `serverActions.allowedOrigins` unless intentionally required and additionally protected.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "next"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "16.0.1"
      }, {
        "fixed" : "16.1.7"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/vercel/next.js/security/advisories/GHSA-mq59-m269-xvcx"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-27978"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/vercel/next.js/commit/a27a11d78e748a8c7ccfd14b7759ad2b9bf097d8"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/vercel/next.js"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/vercel/next.js/releases/tag/v16.1.7"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-352" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-03-17T15:30:14Z",
    "nvd_published_at" : "2026-03-18T00:16:20Z"
  }
}