follow-redirects array-form headers bypass cross-origin credential stripping

Summary

follow-redirects is a Node.js HTTP and HTTPS client wrapper that automatically follows redirects. From version 1.16.0 to before version 1.16.1, follow-redirects removes sensitive credential headers (Authorization, Proxy-Authorization, Cookie, and any caller-declared sensitiveHeaders) before following a redirect that crosses to a different host or downgrades to a less secure protocol. The removal routine iterates the caller's headers container with for...in and matches header names against a filter. This assumes the headers container is a plain object keyed by header names. Node's underlying http.request, which follow-redirects is a drop-in replacement for, also accepts headers as an alternating array of names and values. For an array, for...in yields the numeric indices "0", "1", "2" and so on, which never match a header-name filter, so nothing is removed. An application that sends array-form headers and follows an attacker-controlled cross-origin redirect therefore forwards its Authorization, Cookie, and Proxy-Authorization headers verbatim to the attacker-controlled destination, with no error or warning. The sensitiveHeaders option added to fix CVE-2026-40895 / GHSA-r4q5-vmmm-2653 is equally ineffective, because it relies on the same helper. This is an unauthenticated confidentiality vulnerability: any remote server the victim application contacts can harvest the victim's credential headers by responding with a cross-origin redirect. This issue has been patched in version 1.16.1.

Timeline

1. Oct 20, 2026, 5:58 PM UTCCVE published
2. Oct 22, 2026, 9:34 PM UTCFirst seen by cve.now
3. Oct 23, 2026, 1:59 AM UTCCISA SSVC assessment

   Exploitation: poc · Automatable: no · Technical impact: partial

4. Oct 23, 2026, 1:59 AM UTCRecord last updated

Affected versions

• follow-redirects follow-redirects

  From 1.16.0 · fixed in 1.16.1

• follow-redirectsnpm

  From 1.16.0 · fixed in 1.16.1

References 3