CVE-2026-91766
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 ).
- Published Sep 25, 2026
- CVSS 5.9 medium
- 0.3% chance of exploitation in the next 30 days (EPSS)
- A fix is available
Affected software
In the news
- Multiple vulnerabilities in PHP CERT-FR ·