CVE-2026-27978

4.3 MEDIUM
Published: March 18, 2026 Modified: March 18, 2026
View on NVD

Description

Next.js is a React framework for building full-stack web applications. Starting in version 16.0.1 and prior to version 16.1.7, `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. An attacker could induce a victim browser to submit Server Actions from a sandboxed context, potentially executing state-changing actions with victim credentials (CSRF). This is fixed in version 16.1.7 by treating `'null'` as an explicit origin value and enforcing host/origin checks unless `'null'` is explicitly allowlisted in `experimental.serverActions.allowedOrigins`. If upgrading is not immediately possible, add CSRF tokens for sensitive Server Actions, prefer `SameSite=Strict` on sensitive auth cookies, and/or do not allow `'null'` in `serverActions.allowedOrigins` unless intentionally required and additionally protected.

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://github.com/vercel/next.js/releases/tag/v16.1.7
Source: security-advisories@github.com
Release Notes
https://github.com/vercel/next.js/security/advisories/GHSA-mq59-m269-xvcx
Source: security-advisories@github.com
Vendor Advisory Mitigation

3 reference(s) from NVD

Quick Stats

CVSS v3 Score
4.3 / 10.0
EPSS (Exploit Probability)
0.0%
4th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)

Affected Vendors

vercel