CVE-2026-44578
HIGHCVE-2026-44578 is a high-severity (CVSS 8.6) vulnerability in next. 3 public exploit references exist, so weaponization risk is real. O3 Security confirms whether CVE-2026-44578 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Next.js: Server-side request forgery in applications using WebSocket upgrades
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, a proxy for how much of the ecosystem is exposed.
nextnpmDescription
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | next | ≥ 13.4.13&&< 15.5.16 | 15.5.16 |
| 📦npm | next | ≥ 16.0.0&&< 16.2.5 | 16.2.5 |
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
dinosn/CVE-2026-44578
CVE-2026-44578: Next.js WebSocket Upgrade SSRF — pre-auth credential the
love07oj/nextjs-cve-2026-44578
Nuclei templates for detecting CVE-2026-44578 (Next.js WebSocket Upgrade
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for next. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
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
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-44578 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-44578. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-44578 in your dependencies?
O3 detects CVE-2026-44578 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.