Next.js versions >=9.5.0 and <9.5.4 are vulnerable to an Open Redirect. Specially encoded paths could be used with the trailing slash redirect to allow an open redirect to occur to an external site. In general, this redirect does not directly harm users although can allow for phishing attacks by redirecting to an attackers domain from a trusted domain. The issue is fixed in version 9.5.4.
Use CWE-601, Vercel vendor hub and Next.Js product page to widen CVE-2020-15242 into its surrounding weakness, vendor, and product context.
Compare it with CVE-2025-55182, CVE-2025-67779 and CVE-2025-55184 for nearby disclosures in the same product family. Additional editorial context is available in Cybersecurity Weekly Roundup: April 27, 2026 — Critical Zero-Days and Framework Failures.