Security advisory

{
  "id": "edcdb6ec5ac65bfdbd9a5b1fa638b213f987c53573459be37b0e42802c154324",
  "url": "https://osv.dev/vulnerability/CVE-2021-22903",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2021-22903",
    "summary": "The actionpack ruby gem before 6.1.3.2 suffers from a possible open redirect vulnerability. Specially crafted Host headers in combination with certain \"allowed host\" formats can cause the Host Authorization middleware in Action Pack to redirect users to a malicious website. This is similar to CVE-2021-22881. Strings in config.hosts that do not have a leading dot are converted to regular expressions without proper escaping. This causes, for example, `config.hosts << \"sub.example.com\"` to permit a request with a Host header value of `sub-example.com`.",
    "evidence": "osv:CVE-2021-22903",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2021-22903",
      "aliases": [
        "CVE-2021-22903",
        "GHSA-5hq2-xf89-9jxq"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/rails/rails",
              "type": "GIT",
              "events": [
                {
                  "introduced": "5f3ff60084ab5d5921ca3499814e4697f8350ee7"
                },
                {
                  "fixed": "75ac626c4e21129d8296d4206a1960563cc3d4aa"
                },
                {
                  "introduced": "b38eb45ad9cb2041b30ac5d4d7b5b6e7b911ff2e"
                },
                {
                  "last_affected": "b38eb45ad9cb2041b30ac5d4d7b5b6e7b911ff2e"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:rubyonrails:rails:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "6.1.1"
                      },
                      {
                        "fixed": "6.1.3.2"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "cpe": "cpe:2.3:a:rubyonrails:rails:6.1.0:rc2:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "6.1.0-rc2"
                      },
                      {
                        "last_affected": "6.1.0-rc2"
                      }
                    ],
                    "source": "CPE_STRING"
                  }
                ]
              }
            }
          ],
          "versions": [
            "6.1.0-rc2",
            "v6.1.3.1",
            "v6.1.3",
            "v6.1.2",
            "v6.1.1",
            "v6.1.0.rc2"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-22903.json"
          }
        }
      ],
      "modified": "2026-10-24T10:31:01.380191908Z",
      "provider": "osv",
      "references": [
        "https://hackerone.com/reports/1148025",
        "https://discuss.rubyonrails.org/t/cve-2021-22903-possible-open-redirect-vulnerability-in-action-pack/77867"
      ],
      "provider_metadata": {}
    },
    "related_cves": [
      {
        "value": "CVE-2021-22903",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 439773,
  "published_at": "2021-06-11T16:15:11.437+00:00"
}