Deno is a JavaScript, TypeScript, and WebAssembly runtime with secure defaults. When you send a request with the Authorization header to one domain, and the response asks to redirect to a different domain, Deno'sfetch() redirect handling creates a follow-up redirect request that keeps the original Authorization header, leaking its content to that second domain. This vulnerability is fixed in 2.1.2.
CVE ID: CVE-2025-21620
CVSS Base Severity: HIGH
CVSS Base Score: 7.5
Vendor: denoland
Product: deno
EPSS Score: 0.04% (probability of being exploited)
EPSS Percentile: 11.48% (scored less or equal to compared to others)
EPSS Date: 2025-02-04 (when was this score calculated)