Security advisory

{
  "id": "a5888e25d4fb80c5d91862fdb26f18b181e1e6100040bfe77123ce6bf2b3d06c",
  "url": "https://osv.dev/vulnerability/CVE-2021-41263",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2021-41263",
    "summary": "rails_multisite provides multi-db support for Rails applications. In affected versions this vulnerability impacts any Rails applications using `rails_multisite` alongside Rails' signed/encrypted cookies. Depending on how the application makes use of these cookies, it may be possible for an attacker to re-use cookies on different 'sites' within a multi-site Rails application. The issue has been patched in v4 of the `rails_multisite` gem. Note that this upgrade will invalidate all previous signed/encrypted cookies. The impact of this invalidation will vary based on the application architecture.",
    "evidence": "osv:CVE-2021-41263",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2021-41263",
      "aliases": [
        "CVE-2021-41263",
        "GHSA-844m-cpr9-jcmh"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/discourse/rails_multisite",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "c6785cdb5c9277dd2c5ac8d55180dd1ece440ed0"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:discourse:rails_multisite:*:*:*:*:*:ruby:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "4.0.0"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "range": [
                      {
                        "fixed": "c6785cdb5c9277dd2c5ac8d55180dd1ece440ed0"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v3.1.0",
            "v3.0.0",
            "v2.5.0",
            "v2.4.0",
            "v2.3.0",
            "v2.1.2",
            "v2.1.1",
            "v2.1.0",
            "v2.0.7",
            "v2.0.2",
            "v2.0.1",
            "v2.0.0",
            "v1.1.2",
            "v1.1.1",
            "v1.0.3",
            "v1.0.2",
            "v1.0.1",
            "v1.0.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-41263.json"
          }
        }
      ],
      "modified": "2026-10-20T10:54:58.570908382Z",
      "provider": "osv",
      "references": [
        "https://github.com/discourse/rails_multisite/security/advisories/GHSA-844m-cpr9-jcmh",
        "https://github.com/discourse/rails_multisite/commit/c6785cdb5c9277dd2c5ac8d55180dd1ece440ed0"
      ],
      "provider_metadata": {}
    },
    "related_cves": [
      {
        "value": "CVE-2021-41263",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 386609,
  "published_at": "2021-11-15T20:15:20.037+00:00"
}