CVE-2026-44578 Next.js: Server-side request forgery in applications using WebSocket upgrades
Attackers can exploit WebSocket upgrades in self-hosted Next.js apps to perform server-side request forgery, exposing internal services or cloud metadata.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-44578?
CVE-2026-44578 is a high-severity server-side request forgery vulnerability in Vercel Next.js, published on 13 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Next.js is a React framework for building full-stack web applications. From 13.4.13 to before 15.5.16 and 16.2.5, self-hosted applications using the built-in Node.js server can be vulnerable to server-side request forgery through crafted WebSocket upgrade requests. An attacker can cause the server to proxy requests to arbitrary internal or external destinations, which may expose internal services or cloud metadata endpoints. Vercel-hosted deployments are not affected. This vulnerability is fixed in 15.5.16 and 16.2.5.
Weakness: CWE-918
Which versions are affected by CVE-2026-44578?
4 open source packages ship an affected version, including next. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
next npm | From 13.4.13 | 15.5.16 |
next npm | From 13.4.13 | 15.5.16 |
next npm | From 16.0.0 | 16.2.5 |
next npm | From 16.0.0 | 16.2.5 |
Products include Vercel Next.js.
How do I fix CVE-2026-44578?
Upgrade next to a fixed version for your release line: 15.5.16 or 16.2.5.
Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.
Is CVE-2026-44578 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-44578 exists.
Public exploit code: 1 Nuclei template and 8 proofs of concept on GitHub.
Other vulnerabilities in Vercel Next.js
- CVE-2025-29927 Authorization Bypass in Next.js Middleware
- CVE-2026-94483 Next.js: Server-Side Request Forgery in Image Optimization
- CVE-2026-64642 Next.js: Middleware / Proxy bypass in App Router applications using Turbopack and single locale
- CVE-2026-64645 Next.js: Server-Side Request Forgery in rewrites via attacker-controlled destination hostname
- CVE-2026-64649 Next.js: Server-Side Request Forgery in Server Actions on Custom Servers
Sources
Also known as CLEANSTART-2026-WQ22617, CLEANSTART-2026-WR08487, GHSA-c4j6-fc7j-m34r, MINI-32r3-hxmf-g53g, MINI-3cq8-qx74-cfx9, MINI-p88j-rx68-3gp2 and 2 more.