SSRF in Vercel Next.js
CVE-2026-44578
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.
Vulnerability class: SSRF (Server-Side Request Forgery)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.6 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N.
EPSS exploit prediction
EPSS: 0.019 (78.8th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 79th percentile — 78.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.389 · newest: 0.019 · change: -0.370
Affected products
- Vercel Next.js — versions >= 16.0.0, < 16.2.5, >= 13.4.13, < 15.5.16
Weakness classification (CWE)
Public proof-of-concept exploits
References
- github.com/vercel/next.js/security/advisories/GHSA-c4j6-fc7j-m34r (Mitigation, Vendor Advisory)
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
Frequently asked questions
- What is CVE-2026-44578?
- CVE-2026-44578 is a high-severity vulnerability in Vercel Next.js, classified under Server-Side Request Forgery (SSRF). CVSS score: 8.6/10. Published 2026-05-13.
- How severe is CVE-2026-44578?
- High severity. CVSS v3 base score is 8.6 out of 10.
- Is CVE-2026-44578 known to be exploited?
- 10 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.