{"cve":"CVE-2026-27978","nvd":{"published":"2026-03-18T00:16:20.117","modified":"2026-06-17T10:28:00.450","status":"Analyzed","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.","cvss_v4":{"vector":"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","score":5.3},"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N","score":4.3},"cwes":["CWE-352"],"references":["https://github.com/vercel/next.js/commit/a27a11d78e748a8c7ccfd14b7759ad2b9bf097d8","https://github.com/vercel/next.js/releases/tag/v16.1.7","https://github.com/vercel/next.js/security/advisories/GHSA-mq59-m269-xvcx"],"products":["vercel:next.js"],"source":"nvd","synced_at":"2026-10-19T22:26:19.218427112+00:00"},"epss":{"cve":"CVE-2026-27978","score":0.00208,"percentile":0.10939,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-mq59-m269-xvcx","url":"https://osv.dev/vulnerability/GHSA-mq59-m269-xvcx","summary":"Next.js: null origin can bypass Server Actions CSRF checks","modified":"2026-03-19T18:31:23.523529Z","packages":[{"ecosystem":"npm","name":"next","purl":"pkg:npm/next","ranges":[">=16.0.1 <16.1.7"],"fixed":["16.1.7"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}