CVE-2026-94482: Next.js: Denial of Service in App Router using Server Actions
Impact
Crafted requests targeting Next.js applications using App Router with at least one Server Action can lead to excessive CPU usage blocking processing of further requests in the same process.
Workarounds
No workaround exists besides upgrading. Applications using Pages Router or not using Server Actions are not vulnerable.
Other sources
Next.js is a React framework for building full-stack web applications. From 13.0.0 until 15.5.28 and 16.4.1, crafted requests targeting App Router applications with at least one Server Action can cause excessive CPU consumption and block processing of further requests in the same process. Applications using the Pages Router and App Router applications without Server Actions are not affected. This issue is fixed in versions 15.5.28 and 16.4.1.
— MITRE
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
npm/nextto a version that resolves this vulnerability.Fixed in 16.4.1 - Upgrade
Upgrade
npm/nextto a version that resolves this vulnerability.Fixed in 15.5.28 - Upgrade
Upgrade
Next.jsto a version that resolves this vulnerability.Fixed in 15.5.28 - Upgrade
Upgrade
Next.jsto a version that resolves this vulnerability.Fixed in 16.4.1
Event History
Frequently Asked Questions
Which applications are affected?
Affected applications use the App Router and have at least one Server Action. Applications that use the Pages Router, or App Router applications with no Server Actions, are not affected.
What does an attacker need to exploit this issue?
An attacker needs to send crafted requests to a vulnerable App Router application that has at least one Server Action. Successful exploitation can consume excessive CPU and block further requests handled by the same process.
What should teams do to remediate the issue?
Upgrade Next.js to version 15.5.28 or 16.4.1. The issue affects versions from 13.0.0 up to the fixed releases.