PT-2026-25909 · Npm · Next

Published 2026-03-17 · Updated 2026-03-17 · CVE-2026-27978

OSV

CVSS v4.0

5.3

5.3

Medium

Base vector

AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N

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.

Fix

CSRF

Weakness Enumeration

CWE-352

Related Identifiers

CVE-2026-27978

GHSA-MQ59-M269-XVCX

Affected Products

Next

References · 5

• https://osv.dev/vulnerability/GHSA-mq59-m269-xvcx · Vendor Advisory
• https://github.com/vercel/next.js · Note
• https://github.com/vercel/next.js/commit/a27a11d78e748a8c7ccfd14b7759ad2b9bf097d8 · Note
• https://github.com/vercel/next.js/releases/tag/v16.1.7 · Note
• https://github.com/vercel/next.js/security/advisories/GHSA-mq59-m269-xvcx · Note