Devise: Open Redirect via Unvalidated `request.referrer` in Timeoutable Session Timeout Handler

{
  "id": "2887c3ed919e3ad5979a17dc8506d77aac075d5af04ec20bcef58c3990819f86",
  "url": "https://osv.dev/vulnerability/CVE-2026-40295",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Devise: Open Redirect via Unvalidated `request.referrer` in Timeoutable Session Timeout Handler",
    "summary": "Devise is an authentication solution for Rails based on Warden. In versions 5.0.3 and below, when the Timeoutable module is enabled in Devise, the FailureApp#redirect_url method returns request.referrer — the HTTP Referer header, which is attacker-controllable — without validation for any non-GET request that results in a session timeout. An attacker who hosts a page with an auto-submitting cross-origin form can cause a victim with an expired Devise session to be redirected to an arbitrary external URL. This contrasts with the GET timeout path (which uses server-side attempted_path) and Devise's own store_location_for mechanism (which strips external hosts via extract_path_from_location), both of which are protected; only the non-GET timeout redirect path is unprotected. Expired-session users can be silently redirected from the trusted app domain to attacker-controlled URLs, enabling phishing and malware delivery while bypassing browser warnings. Note: Rails' built-in open-redirect protection does not mitigate this issue. Devise::FailureApp is an ActionController::Metal app with its own isolated copy of the relevant redirect configuration, so config.action_controller.action_on_open_redirect = :raise (and the older raise_on_open_redirects setting) do not reach it. This issue has been fixed in version 5.0.4.",
    "evidence": "osv:CVE-2026-40295",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-40295",
      "aliases": [
        "CVE-2026-40295",
        "GHSA-jp94-3292-c3xv"
      ],
      "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/heartcombo/devise",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "9ea459de9aec5f1217ad738c58e0d23fb9f5beaa"
                },
                {
                  "fixed": "025fe2124f9928766fc46520e999633b598d0360"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:heartcombo:devise:*:*:*:*:*:ruby:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "5.0.4"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "range": [
                      {
                        "fixed": "025fe2124f9928766fc46520e999633b598d0360"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v5.0.3",
            "v5.0.2",
            "v5.0.1",
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            "v0.8.1",
            "v0.8.0",
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          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-40295.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:26.749434464Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/40xxx/CVE-2026-40295.json",
        "https://github.com/heartcombo/devise/security/advisories/GHSA-jp94-3292-c3xv",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-40295",
        "https://github.com/heartcombo/devise/commit/025fe2124f9928766fc46520e999633b598d0360"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-601"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/40xxx/CVE-2026-40295.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-40295",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 493279,
  "published_at": "2026-05-22T19:10:57.039+00:00"
}