CVE-2026-52845

Caddy is an extensible server platform that uses TLS by default. Prior to 2.11.4, forward_auth copy_headers deletes the exact client-supplied identity header before copying the trusted value from the auth gateway. But when the request later goes through php_fastcgi, Caddy normalizes HTTP headers into CGI variables by replacing - with _. This lets a client send an underscore alias that survives the forward_auth delete step but becomes the same PHP/FastCGI variable. Result: a remote client can inject or sometimes override identity/group headers trusted by PHP/FastCGI applications behind Caddy. This vulnerability is fixed in 2.11.4.

• CWE-287
• CWE-290
• CWE-444
• CWE-444

• https://github.com/caddyserver/caddy/security/advisories/GHSA-f59h-q822-g45gExploit, Third Party Advisory
• https://access.redhat.com/security/cve/CVE-2026-52845
• https://bugzilla.redhat.com/show_bug.cgi?id=2491907
• https://github.com/caddyserver/caddy/security/advisories/GHSA-f59h-q822-g45gExploit, Third Party Advisory
• https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-52845.json

Published

Jun 23, 2026

Last Modified

Jul 15, 2026

Status

Modified

• How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
• Same Subject, Wrong User: A Cross-Issuer Account Takeover in n8nStrix found an identity-binding bug in n8n's token-exchange flow enabling account takeover.
• Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
• PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
• AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.

• CVE-2026-5284Use after free in Dawn in Google Chrome prior to 146.0.7680.…7.5
• CVE-2026-52840Easy!Appointments is a self hosted appointment scheduler. In…2.7
• CVE-2026-52841Easy!Appointments is a self hosted appointment scheduler. In…3.1
• CVE-2026-52842Lightpanda is a headless browser designed for AI and automat…9.3
• CVE-2026-52843Lightpanda is a headless browser designed for AI and automat…9.3
• CVE-2026-52844Caddy is an extensible server platform that uses TLS by defa…7.5
• CVE-2026-52846Caddy is an extensible server platform that uses TLS by defa…4.2
• CVE-2026-5285Use after free in WebGL in Google Chrome prior to 146.0.7680…8.8
• CVE-2026-52855Wings is the server control plane for Pterodactyl, a free, o…9.9
• CVE-2026-52856Wings is the server control plane for Pterodactyl, a free, o…7.5
• CVE-2026-52857Wings is the server control plane for Pterodactyl, a free, o…5.5
• CVE-2026-52858Vim is an open source, command line text editor. Prior to ve…7.8