CVE-2026-44578 | Next.js: Server-side request forgery in applications using WebSocket upgrades

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.

Published: 2026-05-13 Last update: 2026-05-14 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-44578 is rated High Risk (66.9/100): CVSS High severity, with high exploitation likelihood (EPSS 5.81%, 91th percentile). EPSS ranks this CVE among the most likely to be exploited in the near term. High exploitation likelihood—assess exposure and prioritize remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-44578

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-05-31 5.04% 5.81% +0.77%
2 2026-05-22 4.48% 5.04% +0.56%
3 2026-05-19 — 4.48% —

Full EPSS history (5 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-44578

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.6 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 4.0 [email protected]

Weakness enumeration for CVE-2026-44578

GitHub Security Advisory for CVE-2026-44578

GHSA-c4j6-fc7j-m34r · Severity: high · Ecosystem: npm — Next.js vulnerable to server-side request forgery in applications using WebSocket upgrades

Affected software / configurations for CVE-2026-44578

Vendor Product Version Raw CPE
vercel next.js >= 13.4.13, < 15.5.16 cpe:2.3:a:vercel:next.js:*:*:*:*:*:node.js:*:*
vercel next.js >= 16.0.0, < 16.2.5 cpe:2.3:a:vercel:next.js:*:*:*:*:*:node.js:*:*

References for CVE-2026-44578

cvelogic Threat Intelligence