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.
References
Configurations
History
25 Oct 2026, 23:10
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Information
Published : 2026-06-23 18:18
Updated : 2026-10-25 23:10
NVD link : CVE-2026-52845
Mitre link : CVE-2026-52845
CVE.ORG link : CVE-2026-52845
JSON object : View
Products Affected
caddyserver
- caddy
