Next.js is one of the most widely deployed JavaScript frameworks for web applications; organizations using it with WebSocket features face a risk of attackers pivoting from their public-facing web tier into internal infrastructure. In cloud-hosted environments, exploitation could expose cloud provider credentials via metadata service access, potentially leading to account-level compromise. If internal APIs handling customer data or business logic are reachable from the Next.js server, an attacker may access or exfiltrate that data without authentication, creating regulatory exposure under GDPR, CCPA, or sector-specific frameworks depending on the data involved.
You Are Affected If
You run the 'next' npm package in a production application (exact vulnerable version range not confirmed — verify against GHSA-c4j6-fc7j-m34r advisory)
Your Next.js application uses WebSocket upgrade functionality (the vulnerability is specific to this code path)
Your Next.js application server has network access to internal services, cloud metadata endpoints, or private APIs
Your deployment does not enforce outbound egress filtering from the application tier
You have not yet applied the patched version of next as identified in the GitHub or OSV advisory
Board Talking Points
A high-severity flaw in the Next.js web framework can allow an external attacker to reach internal systems through our public-facing web applications.
Engineering teams should identify affected applications and apply the vendor patch within 72 hours of confirmed patch availability, with network-level controls applied immediately as an interim measure.
Without action, an attacker could use this vulnerability to access internal APIs or cloud credentials, potentially expanding a single web application compromise into a broader infrastructure breach.
