CVE-2026-45074: Symfony/security http Symfony's Cas2Handler Derives CAS Service Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-j8gj-9rm5-4xhx",
  "modified" : "2026-05-27T21:11:59Z",
  "published" : "2026-05-27T21:11:59Z",
  "aliases" : [ "CVE-2026-45074" ],
  "summary" : "Symfony's Cas2Handler Derives CAS service URL from Client Host Header → Cross-Service Ticket Replay",
  "details" : "`Cas2Handler` builds this `service` parameter from `Request::getSchemeAndHttpHost()`, which reflects the attacker-controlled HTTP `Host` header whenever Symfony's `framework.trusted_hosts` setting is not configured (the default). An attacker who controls any *other* application registered with the same CAS server can replay a victim's ticket against the Symfony application, with a spoofed `Host` header, and be authenticated as that victim.\n\n### Resolution\n\nA new required `service_url` configuration option is introduced on `Cas2Handler`. The CAS `service` parameter sent to the validation endpoint is now built from this configured URL instead of being derived from the request's `Host` header, preventing cross-service ticket replay via Host header spoofing.\n\nThe patch for this issue is available [here](https://github.com/symfony/symfony/commit/5ba145dba702404801bdf9e7e8d6df170060d541) for branch 7.4.\n\n### Credits\n\nSymfony would like to thank Claude Mythos Preview (via Project Glasswing) for reporting the issue and Nicolas Grekas for providing the fix.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:U"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "symfony/security-http"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "7.1.0"
      }, {
        "fixed" : "7.4.12"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "symfony/security-http"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "8.0.0"
      }, {
        "fixed" : "8.0.12"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "symfony/symfony"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "7.1.0"
      }, {
        "fixed" : "7.4.12"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "symfony/symfony"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "8.0.0"
      }, {
        "fixed" : "8.0.12"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/symfony/symfony/security/advisories/GHSA-j8gj-9rm5-4xhx"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/symfony/symfony/commit/5ba145dba702404801bdf9e7e8d6df170060d541"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/security-http/CVE-2026-45074.yaml"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/symfony/CVE-2026-45074.yaml"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/symfony/symfony"
  }, {
    "type" : "WEB",
    "url" : "https://symfony.com/cve-2026-45074"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-290" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-05-27T21:11:59Z",
    "nvd_published_at" : null
  }
}