CVE-2026-91766 Cross-origin credential leak in HTTP stream wrapper redirects
Attackers can steal sensitive credentials like cookies and authorization headers when PHP's HTTP stream wrapper follows cross-origin redirects.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-91766?
CVE-2026-91766 is a medium-severity vulnerability in Php Php, published on 25 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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 ).
Which versions are affected by CVE-2026-91766?
3 open source packages ship an affected version, including libphp, php and php-min. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
libphp Bitnami | From 8.2.0 | 8.2.34, 8.3.35, 8.4.26, 8.5.11 |
php Bitnami | From 8.2.0 | 8.2.34, 8.3.35, 8.4.26, 8.5.11 |
php-min Bitnami | From 8.2.0 | 8.2.34, 8.3.35, 8.4.26, 8.5.11 |
Products include Php Php.
How do I fix CVE-2026-91766?
Upgrade libphp to a fixed version for your release line: 8.2.34, 8.3.35, 8.4.26 or 8.5.11.
Is CVE-2026-91766 being exploited?
There is no known exploitation of CVE-2026-91766 in the wild and no public exploit code.
Other vulnerabilities in Php Php
Sources
Also known as AZL-104916, BELL-CVE-2026-91766, BIT-libphp-2026-91766, BIT-php-2026-91766, BIT-php-min-2026-91766, CLEANSTART-2026-GS69152 and 11 more.