SSRF in Next.js Server Actions (v14.1.115.5.20, 16.0.016.2.10)
CVE-2026-64649 Published on July 27, 2026
Next.js: Server-Side Request Forgery in Server Actions on Custom Servers
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.
Vulnerability Analysis
CVE-2026-64649 can be exploited with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity and availability.
Weakness Type
What is a SSRF Vulnerability?
The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination. By providing URLs to unexpected hosts or ports, attackers can make it appear that the server is sending the request, possibly bypassing access controls such as firewalls that prevent the attackers from accessing the URLs directly. The server can be used as a proxy to conduct port scanning of hosts in internal networks, use other URLs such as that can access documents on the system (using file://), or use other protocols such as gopher:// or tftp://, which may provide greater control over the contents of requests.
CVE-2026-64649 has been classified to as a SSRF vulnerability or weakness.
Products Associated with CVE-2026-64649
stack.watch emails you whenever new vulnerabilities are published in Vercel Next Js or Red Hat Kafka. Just hit a watch button to start following.
Affected Versions
vercel next.js:- Version >= 14.1.1, < 15.5.21 is affected.
- Version >= 16.0.0 < 16.2.11 is affected.