CVE-2026-44578

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.

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CVSS v3.1 Score

8.6

HIGH

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

EPSS — Exploit Prediction

0.0722

Probability of exploitation

0.92%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-918 Server-Side Request Forgery (SSRF)

Affected Products

Vendor	Product	Versions
vercel	next.js	13.4.13 — 15.5.16
vercel	next.js	16.0.0 — 16.2.5

References

Advisories & Patches

https://github.com/vercel/next.js/security/advisories/GHSA-c4j6-fc7j-m34r

Frequently Asked Questions

What is 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. It has a CVSS v3.1 base score of 8.6 (HIGH).

How severe is CVE-2026-44578? +

CVE-2026-44578 has a CVSS v3.1 score of 8.6 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0722, placing it in the 1th percentile for exploitation probability.

What products are affected by CVE-2026-44578? +

CVE-2026-44578 affects products from vercel, specifically: next.js. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-44578? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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