Copyright © 2012 Red Hat, Inc. All rights reserved. Important 2026-07-27T19:27:58 next: Next.js: Server-Side Request Forgery via malicious host redirection in Server Actions 8.2 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N CWE-918

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.

A flaw was found in Next.js, a framework for building web applications. A remote attacker can exploit this vulnerability by manipulating Host-associated headers when a Server Action forwards or redirects a request. This can lead to Server-Side Request Forgery (SSRF), where the server is tricked into making requests to an attacker-controlled host. Such an attack could potentially expose internal system information or bypass authorization controls.

This Important Server-Side Request Forgery (SSRF) flaw in Next.js Server Actions allows an attacker to redirect outbound requests to a malicious host. This is particularly relevant for Red Hat customers deploying Next.js applications on custom servers or without a proxy that enforces host header validation, as it could lead to unauthorized internal network access or information disclosure. Managed hosting environments and applications using `next start` or standalone output from version 14.2 onwards are not affected. Red Hat Enterprise Linux 10 Affected firefox Red Hat Enterprise Linux 10 Affected thunderbird Red Hat Enterprise Linux 7 Affected firefox Red Hat Enterprise Linux 8 Affected firefox Red Hat Enterprise Linux 8 Affected thunderbird Red Hat Enterprise Linux 9 Affected firefox Red Hat Enterprise Linux 9 Affected thunderbird Red Hat Enterprise Linux AI (RHEL AI) 3 Affected rhelai3/bootc-cuda-rhel9 Red Hat Enterprise Linux AI (RHEL AI) 3 Affected rhelai3/bootc-gaudi-rhel9 Red Hat Enterprise Linux AI (RHEL AI) 3 Affected rhelai3/bootc-rocm-rhel9 Red Hat Enterprise Linux AI (RHEL AI) 3 Affected rhelai3/disk-image-cuda-rhel9 Red Hat Trusted Artifact Signer Not affected rhtas/rekor-search-ui-rhel9 streams for Apache Kafka 2 Affected next streams for Apache Kafka 3 Affected next https://www.cve.org/CVERecord?id=CVE-2026-64649 https://nvd.nist.gov/vuln/detail/CVE-2026-64649 https://github.com/vercel/next.js/commit/b51206321854193208c0805ba42acc49287f942b https://github.com/vercel/next.js/commit/e3e5666ccead3a15162793d697af5e48b7cc0498 https://github.com/vercel/next.js/releases/tag/v15.5.21 https://github.com/vercel/next.js/releases/tag/v16.2.11 https://github.com/vercel/next.js/security/advisories/GHSA-89xv-2m56-2m9x