CVE-2026-91766 — Cross-origin credential leak in HTTP stream wrapper redirects
When the http:// stream wrapper follows a redirect it forwards the user-supplied Authorization, Cookie and Proxy-Authorization headers unchanged, even when the redirect target i…
Published: 2026-09-25 · CVSS: 5.9 · CVSS 3.1
When the http:// stream wrapper follows a redirect it forwards the user-supplied Authorization, Cookie and Proxy-Authorization headers unchanged, even when the redirect target is a different host, a different port, or a downgrade from HTTPS to HTTP. A server that can steer a redirect therefore receives credentials that were only meant for the original origin. This is the same class of issue that libcurl fixed in 7.58.0 ( CVE-2018-1000007 https://github.com/advisories/GHSA-g7x2-hrfp-pv5f ).
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7