Vercel Next.js up to 15.5.20/16.2.10 App Router memory allocation

Summaryinfo

A vulnerability was found in Vercel Next.js up to 15.5.20/16.2.10. It has been declared as problematic. This affects an unknown part of the component App Router. The manipulation results in memory allocation. This vulnerability is known as CVE-2026-64646. It is possible to launch the attack remotely. No exploit is available.

Detailsinfo

A vulnerability was found in Vercel Next.js up to 15.5.20/16.2.10. It has been classified as problematic. Affected is some unknown processing of the component App Router. The manipulation with an unknown input leads to a memory allocation vulnerability. CWE is classifying the issue as CWE-789. The product allocates memory based on an untrusted, large size value, but it does not ensure that the size is within expected limits, allowing arbitrary amounts of memory to be allocated. This is going to have an impact on availability. CVE summarizes:

Next.js is a React framework for building full-stack web applications. In versions 13.0.0 through 15.5.20 and 16.0.0 through 16.2.10, requests targeting Next.js applications using App Router with at least one Server Action can lead to excessive memory consumption if that Server Actions uses the Edge runtime. This issue has been fixed in versions 15.5.21 and 16.2.11.

The advisory is available at github.com. This vulnerability is traded as CVE-2026-64646 since 07/20/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. The technical details are unknown and an exploit is not available.

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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