GHSA-MQ59-M269-XVCX
Vulnerability from github – Published: 2026-03-17 15:30 – Updated: 2026-03-19 18:28Summary
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.
{
"affected": [
{
"package": {
"ecosystem": "npm",
"name": "next"
},
"ranges": [
{
"events": [
{
"introduced": "16.0.1"
},
{
"fixed": "16.1.7"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-27978"
],
"database_specific": {
"cwe_ids": [
"CWE-352"
],
"github_reviewed": true,
"github_reviewed_at": "2026-03-17T15:30:14Z",
"nvd_published_at": "2026-03-18T00:16:20Z",
"severity": "MODERATE"
},
"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 `\u0027null\u0027` as an explicit origin value and enforcing host/origin checks unless `\u0027null\u0027` 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 `\u0027null\u0027` in `serverActions.allowedOrigins` unless intentionally required and additionally protected.",
"id": "GHSA-mq59-m269-xvcx",
"modified": "2026-03-19T18:28:49Z",
"published": "2026-03-17T15:30:14Z",
"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"
}
],
"schema_version": "1.4.0",
"severity": [
{
"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",
"type": "CVSS_V4"
}
],
"summary": "Next.js: null origin can bypass Server Actions CSRF checks"
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
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- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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