Vercel Next.js up to 15.5.20/16.2.10 server-side request forgery

Summaryinfo

A vulnerability classified as critical has been found in Vercel Next.js up to 15.5.20/16.2.10. This impacts an unknown function. This manipulation causes server-side request forgery. This vulnerability is tracked as CVE-2026-64649. The attack is possible to be carried out remotely. No exploit exists.

Detailsinfo

A vulnerability has been found in Vercel Next.js up to 15.5.20/16.2.10 and classified as critical. Affected by this vulnerability is some unknown processing. The manipulation with an unknown input leads to a server-side request forgery vulnerability. The CWE definition for the vulnerability is CWE-918. 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. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

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.

The advisory is shared at github.com. This vulnerability is known as CVE-2026-64649 since 07/20/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Neither technical details nor an exploit are publicly available.

The vulnerability scanner Nessus provides a plugin with the ID 330088 (Next.js Framework 14.1.1 < 15.5.21 / 16.x < 16.2.11 SSRF), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 15.5.21 or 16.2.11 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (330088). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Type

• JavaScript Library

Vendor

• Vercel

Name

• Next.js

Version

• 15.5.0
• 15.5.1
• 15.5.2
• 15.5.3
• 15.5.4
• 15.5.5
• 15.5.6
• 15.5.7
• 15.5.8
• 15.5.9
• 15.5.10
• 15.5.11
• 15.5.12
• 15.5.13
• 15.5.14
• 15.5.15
• 15.5.16
• 15.5.17
• 15.5.18
• 15.5.19
• 15.5.20
• 16.2.0
• 16.2.1
• 16.2.2
• 16.2.3
• 16.2.4
• 16.2.5
• 16.2.6
• 16.2.7
• 16.2.8
• 16.2.9
• 16.2.10

Website

• Product: https://github.com/vercel/next.js/

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If you want to get the best quality for vulnerability data then you always have to consider VulDB.

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