GHSA-c4j6-fc7j-m34r CVE-2026-44578

Next.js vulnerable to server-side request forgery in applications using WebSocket upgrades

High npm

Severity: 8.6 / 10; High · CVSS 3.1
Exploit chance (EPSS): 35.54%; Chance of exploitation in the next 30 days. Higher than 98.45% of scored vulnerabilities.
Known exploited: No; Not in CISA's catalog
Weakness: CWE-918 Server-Side Request Forgery (SSRF)
Fix: 15.5.16; Upgrade next to this version or later

Description

Impact

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.

Fix

We now apply the same safety checks to WebSocket upgrade handling that already existed for normal HTTP requests, so upgrade requests are only proxied when routing has explicitly marked them as safe external rewrites.

Workarounds

If you cannot upgrade immediately, do not expose the origin server directly to untrusted networks. If WebSocket upgrades are not required, block them at your reverse proxy or load balancer, and restrict origin egress to internal networks and metadata services where possible.

Affected versions

npm

Package	Vulnerable	Fixed in
next	`>= 13.4.13, < 15.5.16`	`15.5.16`
next	`>= 16.0.0, < 16.2.5`	`16.2.5`

How to fix

Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.

next npm → `15.5.16`

npm

npm install next@15.5.16

yarn

yarn add next@15.5.16

pnpm

pnpm add next@15.5.16

Severity breakdown

CVSS 3.1 8.6

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N

Attack vector: Network
Attack complexity: Low
Privileges required: None
User interaction: None
Scope: Changed
Confidentiality: High
Integrity: None
Availability: None

Weakness

CWE-918: Server-Side Request Forgery (SSRF)

The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.

References

Advisories

nvd.nist.gov/vuln/detail/CVE-2026-44578

Packages

github.com/vercel/next.js

Timeline

May 11, 2026 Published
Oct 26, 2026 Last updated by the source
Oct 31, 2026 Latest EPSS score

Advisory	Severity	Why it's related
GHSA-673q-mjm6-r5xr Next.js: Unauthenticated Remote Code Execution in `use cache` functions returning typed arrays	Critical	Also affects next
GHSA-2464-fhr4-w9xw Next.js: Unauthenticated Remote Code Execution in Image Optimization API when SVG files are used	Critical	Also affects next
GHSA-p3m5-59mp-jv5r Next.js: Denial of Service in App Router using Server Actions	High	Also affects next
GHSA-3w37-wq28-93x7 Next.js: Pending `use cache` fill can leak Draft Mode content into regular responses and persisted pages	Medium	Also affects next
GHSA-4jqv-mc3x-m676 Next.js has cache poisoning of SSG and ISR pages in self-hosted applications	Medium	Also affects next
GHSA-39w2-rjm5-chcv Next.js has information disclosure in development server's Model Context Protocol endpoint	Medium	Also affects next
GHSA-f87g-xv8r-7p7x Next.js has information disclosure in App Router metadata image routes via dynamicParams bypass	Medium	Also affects next
GHSA-mcj8-r9mp-w47p Next.js has cache poisoning in SSG/ISR rendering that leads to cross-user content substitution and persistent denial of service	Medium	Also affects next

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