{"id":"CVE-2026-64649","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-64649","generatedAt":"2026-10-28T10:40:10.595Z","title":"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).","description":"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":"2026-07-27T20:16:41.000Z","lastModified":"2026-10-24T13:10:00.000Z","status":"Analyzed","sourceIdentifier":"security-advisories@github.com","cvss":{"version":"4.0","score":8.3,"severity":"HIGH","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M"},"cwe":["CWE-918"],"affected":["vercel/next.js"],"epss":{"score":0.00459,"percentile":0.39621,"date":"2026-10-27","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.46%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"https://github.com/vercel/next.js/commit/b51206321854193208c0805ba42acc49287f942b","tags":["Patch"],"source":"security-advisories@github.com"},{"url":"https://github.com/vercel/next.js/commit/e3e5666ccead3a15162793d697af5e48b7cc0498","tags":["Patch"],"source":"security-advisories@github.com"},{"url":"https://github.com/vercel/next.js/releases/tag/v15.5.21","tags":["Product","Release Notes"],"source":"security-advisories@github.com"},{"url":"https://github.com/vercel/next.js/releases/tag/v16.2.11","tags":["Product","Release Notes"],"source":"security-advisories@github.com"},{"url":"https://github.com/vercel/next.js/security/advisories/GHSA-89xv-2m56-2m9x","tags":["Mitigation","Vendor Advisory"],"source":"security-advisories@github.com"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-64649","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}