How severe is CVE-2026-44578?

CVE-2026-44578 has a CVSS score of 8.6/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2026-44578?

CVE-2026-44578 affects the following packages: next (npm), next (npm). Ecosystems affected: npm.

How do I fix CVE-2026-44578?

Update next to 15.5.16 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-44578 is resolved across your whole dependency graph.

How do I detect CVE-2026-44578 in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for next, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-44578 if there is no patch (or I can't update yet)?

Restrict outbound requests from the affected component to an allowlist of hosts, block access to link-local and internal address ranges at the network layer, and require authentication on internal services so a forged request cannot reach them unauthenticated.

Is CVE-2026-44578 actively exploited in the wild?

Yes. There are 3 known exploit references for CVE-2026-44578, including . All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2026-44578?

CVE-2026-44578 has an EPSS (Exploit Prediction Scoring System) score of 35.5%, placing it in the 98th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score warrants monitoring and prompt remediation.

What type of vulnerability is CVE-2026-44578?

CVE-2026-44578 is classified as Server-Side Request Forgery (SSRF) (CWE-918). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2026-44578 published, and has it been updated?

CVE-2026-44578 was published on May 13, 2026 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦

📦 npm

Not in CISA KEV

HIGH severity

CVE-2026-44578 — next

HIGH

CVE-2026-44578 is a high-severity (CVSS 8.6) Server-Side Request Forgery (SSRF) vulnerability in next. 3 public exploit or proof-of-concept references are indexed, so weaponization risk is real. A fix is available for next — see the affected versions and patch details below.

Next.js: Server-side request forgery in applications using WebSocket upgrades

Also known asGHSA-c4j6-fc7j-m34r

Published

May 13, 2026

Updated

Oct 28, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

3 known

Exploitation data as of Nov 10, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-44578.

EPSS Exploitation Probability

via FIRST.org ↗

35.5%probability of exploitation in next 30 days

Moderate Risk0.00%

Lower risk than most CVEs98th percentile — riskier than 98% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

2 pkgs affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

61Kother npm packages depend on this — each one inherits the vulnerability until it's patched upstream

nextnpm

92.1Mdownloads / week

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 Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`next`	≥ 13.4.13&&< 15.5.16	15.5.16`npm install next@15.5.16`
📦npm	`next`	≥ 16.0.0&&< 16.2.5	16.2.5`npm install next@16.2.5`

Affected Products

1 product · 2 configurations

Application

next.jsvercel

≥ 16.0.0 && < 16.2.5

range

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

ynsmroztas/nextssrf

NextSSRF — CVE-2026-44578 Scanner & Exploit ║ ║ Next.js WebSo

⭐ 77🍴 21Sep 2026

dinosn/CVE-2026-44578

CVE-2026-44578: Next.js WebSocket Upgrade SSRF — pre-auth credential the

⭐ 9🍴 2Jul 2026

love07oj/nextjs-cve-2026-44578

Nuclei templates for detecting CVE-2026-44578 (Next.js WebSocket Upgrade

⭐ 8🍴 1Sep 2026

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for next, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update next to 15.5.16 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-44578 is resolved across your whole dependency graph.
Workarounds
Restrict outbound requests from the affected component to an allowlist of hosts, block access to link-local and internal address ranges at the network layer, and require authentication on internal services so a forged request cannot reach them unauthenticated.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatImportant

This Important severity flaw in Next.js affects self-hosted applications, including Red Hat AMQ, when using the built-in Node.js server. A remote attacker can exploit specially crafted WebSocket upgrade requests to perform Server-Side Request Forgery, potentially exposing internal network services or sensitive cloud…

Workaround published by Red Hat

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.

Source: Red Hat security advisory for CVE-2026-44578 (CC BY 4.0)

Product	Fixed in	Advisory
Streams for Apache Kafka 2.9.4	`next`	RHSA-2026:34608
Streams for Apache Kafka 3.2.1	`next`	RHSA-2026:54435
Red Hat Trusted Artifact Signer 1.3	`rhtas/rekor-search-ui-rhel9:1783958622`	RHSA-2026:40974
Red Hat Trusted Artifact Signer 1.4	`rhtas/rekor-search-ui-rhel9:1783327185`	RHSA-2026:37272

Frequently Asked Questions

### 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. #

O3 Security · Impact-Aware SCA

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