{"id":"CVE-2026-64649","aliases":["GHSA-89xv-2m56-2m9x"],"url":"https://o3.security/vulnerability/CVE-2026-64649","summary":"Next.js: Server-Side Request Forgery in Server Actions on Custom Servers","details":"Next.js is a React framework for building full-stack web applications. In versions 14.1.1 through 15.5.20 and 16.0.0 through 16.2.10, when a Server Action forwards or redirects a request, an attacker can cause the server to send that outbound request to a malicious host (Server-Side Request Forgery). This requires the attacker's request to control Host-associated headers. In some configurations, it's also possible to obtain internal values that weaken middleware/proxy authorization. Applications that use Server Actions are affected when the incoming host header is not fixed to a trusted value. This typically occurs on custom servers, or on deployments not behind a proxy that pins the host. Managed hosting pins the host upstream and is not affected; next start and standalone output do the same from version 14.2 onward. This issue has been fixed in versions 15.5.21 and 16.2.11.","published":"2026-07-27T19:27:58.865Z","modified":"2026-08-12T03:51:11.595230939Z","cvss":null,"epss":{"score":0.00872,"percentile":0.5652,"asOf":"2026-09-07"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"npm","name":"next","fixedVersion":"15.5.21"},{"ecosystem":"npm","name":"next","fixedVersion":"16.2.11"}],"fix":{"url":"https://github.com/vercel/next.js/commit/b51206321854193208c0805ba42acc49287f942b","label":"vercel/next.js@b512063"},"references":[{"type":"WEB","url":"https://github.com/vercel/next.js/releases/tag/v15.5.21"},{"type":"WEB","url":"https://github.com/vercel/next.js/releases/tag/v16.2.11"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64649.json"},{"type":"ADVISORY","url":"https://github.com/vercel/next.js/security/advisories/GHSA-89xv-2m56-2m9x"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-64649"},{"type":"FIX","url":"https://github.com/vercel/next.js/commit/b51206321854193208c0805ba42acc49287f942b"},{"type":"FIX","url":"https://github.com/vercel/next.js/commit/e3e5666ccead3a15162793d697af5e48b7cc0498"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:11.595230939Z"}}