GHSA-J8GJ-9RM5-4XHX

Vulnerability from github – Published: 2026-05-27 21:11 – Updated: 2026-05-27 21:11
VLAI
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.

Resolution

A 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.

The patch for this issue is available here for branch 7.4.

Credits

Symfony would like to thank Claude Mythos Preview (via Project Glasswing) for reporting the issue and Nicolas Grekas for providing the fix.

Severity
6.6 (Medium)
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
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{
  "affected": [
    {
      "package": {
        "ecosystem": "Packagist",
        "name": "symfony/security-http"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "7.1.0"
            },
            {
              "fixed": "7.4.12"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Packagist",
        "name": "symfony/security-http"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "8.0.0"
            },
            {
              "fixed": "8.0.12"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Packagist",
        "name": "symfony/symfony"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "7.1.0"
            },
            {
              "fixed": "7.4.12"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Packagist",
        "name": "symfony/symfony"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "8.0.0"
            },
            {
              "fixed": "8.0.12"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-45074"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-290"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-05-27T21:11:59Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "`Cas2Handler` builds this `service` parameter from `Request::getSchemeAndHttpHost()`, which reflects the attacker-controlled HTTP `Host` header whenever Symfony\u0027s `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\u0027s 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\u0027s `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.",
  "id": "GHSA-j8gj-9rm5-4xhx",
  "modified": "2026-05-27T21:11:59Z",
  "published": "2026-05-27T21:11:59Z",
  "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"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "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",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Symfony\u0027s Cas2Handler Derives CAS service URL from Client Host Header \u2192 Cross-Service Ticket Replay"
}



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