{"id":"CVE-2026-52845","revision":"94deaed51bec4c72b2bc514ab3cea769","records":[{"revision":"94deaed51bec4c72b2bc514ab3cea769","observedAt":"2026-10-27T14:13:17.111+00:00","statement":{"source":"nvd","id":"CVE-2026-52845","aliases":[],"title":"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…","description":"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.","state":0,"publishedAt":"2026-06-23T18:18:05.267+00:00","modifiedAt":"2026-10-25T23:10:00.167+00:00","affected":[],"metrics":[{"system":"CVSS 3.1 · security-advisories@github.com · Secondary","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N","score":8.1,"severity":"HIGH"},{"system":"CVSS 3.1 · 0b0ca135-0b70-47e7-9f44-1890c2a1c46c · Secondary","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N","score":8.1,"severity":"HIGH"}],"references":["https://github.com/caddyserver/caddy/security/advisories/GHSA-f59h-q822-g45g","https://access.redhat.com/security/cve/CVE-2026-52845","https://bugzilla.redhat.com/show_bug.cgi?id=2491907","https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-52845.json"],"sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-52845","license":"NIST NVD usage terms; underlying source attribution retained","enrichment":{"sourceStatus":"Modified","weaknesses":["CWE-287","CWE-290","CWE-444"],"productCriteria":["cpe:2.3:a:caddyserver:caddy:*:*:*:*:*:*:*:*"],"sourceDates":{"published":"2026-06-23T18:18:05.267","lastModified":"2026-10-25T23:10:00.167"},"relatedAdvisories":[],"note":"NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON."},"key":"nvd:CVE-2026-52845","identifiers":["CVE-2026-52845"]},"retained":false,"historicalAffected":[]}],"coverage":[]}