{"id":"DEBIAN-CVE-2026-52845","details":"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.","modified":"2026-08-27T23:06:12.152612101Z","published":"2026-06-23T18:18:05.267Z","upstream":["CVE-2026-52845"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2026-52845"}],"affected":[{"package":{"name":"caddy","ecosystem":"Debian:12","purl":"pkg:deb/debian/caddy?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.11.2-1","2.11.2-1~bpo13+1","2.11.4-1","2.6.2-10","2.6.2-11","2.6.2-12","2.6.2-13","2.6.2-14","2.6.2-5","2.6.2-6","2.6.2-6.1","2.6.2-7","2.6.2-8","2.6.2-9"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2026-52845.json"}},{"package":{"name":"caddy","ecosystem":"Debian:13","purl":"pkg:deb/debian/caddy?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.6.2-12+deb13u1"}]}],"versions":["2.6.2-12"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2026-52845.json"}},{"package":{"name":"caddy","ecosystem":"Debian:14","purl":"pkg:deb/debian/caddy?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.11.4-1"}]}],"versions":["2.11.2-1","2.11.2-1~bpo13+1","2.6.2-12","2.6.2-13","2.6.2-14"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2026-52845.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N"}]}