CVE-2026-27978— Next.js: null origin can bypass Server Actions CSRF checks

Next.js: null origin can bypass Server Actions CSRF checks

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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跨站请求伪造(CSRF)

Next.js 安全漏洞

Next.js是Vercel开源的一个 React 框架。 Next.js 16.0.1至16.1.7之前版本存在安全漏洞，该漏洞源于服务器操作CSRF验证期间将origin: null视为缺失来源，可能导致绕过来源验证，引发跨站请求伪造攻击。

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