CVE-2026-52845

{"id": "CVE-2026-52845", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-52845", "role": "CISA Coordinator", "options": [{"exploitation": "poc"}, {"automatable": "no"}, {"technicalImpact": "total"}], "version": "2.0.3", "timestamp": "2026-06-24T14:25:18.472130Z"}}], "cvssMetricV31": [{"type": "Secondary", "source": "security-advisories@github.com", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 8.1, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "NONE", "privilegesRequired": "LOW", "confidentialityImpact": "HIGH"}, "impactScore": 5.2, "exploitabilityScore": 2.8}, {"type": "Secondary", "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 8.1, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "NONE", "privilegesRequired": "LOW", "confidentialityImpact": "HIGH"}, "impactScore": 5.2, "exploitabilityScore": 2.8}]}, "affected": [{"source": "security-advisories@github.com", "affectedData": [{"vendor": "caddyserver", "product": "caddy", "versions": [{"status": "affected", "version": "< 2.11.4"}]}]}, {"source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c", "affectedData": [{"cpes": ["cpe:/a:redhat:hummingbird:1"], "vendor": "Red Hat", "product": "Red Hat Hardened Images", "packageName": "caddy", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "defaultStatus": "unaffected"}]}], "published": "2026-06-23T18:18:05.267", "references": [{"url": "https://github.com/caddyserver/caddy/security/advisories/GHSA-f59h-q822-g45g", "tags": ["Exploit", "Third Party Advisory"], "source": "security-advisories@github.com"}, {"url": "https://access.redhat.com/security/cve/CVE-2026-52845", "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c"}, {"url": "https://bugzilla.redhat.com/show_bug.cgi?id=2491907", "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c"}, {"url": "https://github.com/caddyserver/caddy/security/advisories/GHSA-f59h-q822-g45g", "tags": ["Exploit", "Third Party Advisory"], "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"}, {"url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-52845.json", "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c"}], "vulnStatus": "Modified", "weaknesses": [{"type": "Secondary", "source": "security-advisories@github.com", "description": [{"lang": "en", "value": "CWE-287"}, {"lang": "en", "value": "CWE-290"}, {"lang": "en", "value": "CWE-444"}]}, {"type": "Secondary", "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c", "description": [{"lang": "en", "value": "CWE-444"}]}], "descriptions": [{"lang": "en", "value": "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."}], "lastModified": "2026-07-15T01:16:22.240", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:caddyserver:caddy:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "6CC2FFA3-3F35-452A-A0B6-C1B66C0C73E6", "versionEndExcluding": "2.11.4"}], "operator": "OR"}]}], "sourceIdentifier": "security-advisories@github.com"}