Vercel Next.js up to 15.5.20/16.2.10 information disclosure

Summaryinfo

A vulnerability has been found in Vercel Next.js up to 15.5.20/16.2.10 and classified as problematic. The impacted element is an unknown function. This manipulation causes information disclosure. This vulnerability appears as CVE-2026-64643. The attack may be initiated remotely. There is no available exploit.

Detailsinfo

A vulnerability was found in Vercel Next.js up to 15.5.20/16.2.10. It has been declared as problematic. Affected by this vulnerability is an unknown part. The manipulation with an unknown input leads to a information disclosure vulnerability. The CWE definition for the vulnerability is CWE-200. The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information. As an impact it is known to affect confidentiality. The summary by CVE is:

Next.js is a React framework for building full-stack web applications. In versions 12.0.0 through 15.5.20 and 16.0.0 through 16.2.10, Next.js applications using App Router, Server Actions (use server) or use cache endpoints can be disclosed bypassing any authentication on the pages where these endpoints are usually used. Server Action IDs can be disclosed to unauthenticated users via publicly served client artifacts (for example, static chunks containing action references). Affected users are applications using App Router and Server Actions. By itself, this disclosure is typically a recon/enumeration primitive; however, it can increase risk when combined with other weaknesses. 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-2026-64643 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. MITRE ATT&CK project uses the attack technique T1592 for this issue.

Upgrading to version 15.5.21 or 16.2.11 eliminates this vulnerability.

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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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