CVE-2026-40295: Devise Devise Has An Open Redirect Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-jp94-3292-c3xv",
  "modified" : "2026-05-29T21:44:44Z",
  "published" : "2026-05-08T15:41:47Z",
  "aliases" : [ "CVE-2026-40295" ],
  "summary" : "Devise has an Open Redirect via Unvalidated `request.referrer` in Timeoutable Session Timeout Handler",
  "details" : "## Summary\n\nWhen 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.\n\n## Details\n\nThe vulnerable code is in `lib/devise/failure_app.rb`:\n\n```ruby\ndef redirect_url\n  if warden_message == :timeout\n    flash[:timedout] = true if is_flashing_format?\n\n    path = if request.get?\n      attempted_path          # safe: server-side value from warden options\n    else\n      request.referrer        # UNSAFE: HTTP Referer header, attacker-controlled\n    end\n\n    path || scope_url\n  else\n    scope_url\n  end\nend\n```\n\nThis is passed directly to `redirect_to`:\n\n```ruby\ndef redirect\n  store_location!\n  # ...\n  redirect_to redirect_url   # redirect_url may be an external attacker URL\nend\n```\n\nThe GET timeout path uses `attempted_path`, which is set server-side by Warden and cannot be influenced by the client. The `store_location!` method also only runs for GET requests, so no session-based protection is applied on POST timeouts.\n\nBy contrast, Devise's `store_location_for` method (used elsewhere) correctly sanitizes URLs via `extract_path_from_location`, which strips the scheme and host.\n\n## Impact\n\n- Victims with expired sessions who click any attacker-crafted link or visit an attacker page with an auto-submitting form are redirected to an arbitrary external URL.\n- The redirect happens transparently via a trusted domain (the target app's domain), bypassing browser phishing warnings.\n- An attacker can redirect victims to a fake login page to harvest credentials (phishing), or to malicious download sites.\n\n_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.\n\n## Patches\n\nThis is patched in Devise v5.0.4. Users should upgrade as soon as possible.\n\n## Workaround\n\nNone beyond upgrading. If an upgrade is not immediately possible, the same changes from the patch commit can be applied as a monkey-patch in a Rails initializer (`Devise::FailureApp#redirect_url` and `Devise::Controllers::StoreLocation#extract_path_from_location`). Remove the monkey-patch after upgrading.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "RubyGems",
      "name" : "devise"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "5.0.4"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 5.0.3"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/heartcombo/devise/security/advisories/GHSA-jp94-3292-c3xv"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-40295"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/heartcombo/devise/commit/025fe2124f9928766fc46520e999633b598d0360"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/heartcombo/devise"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/rubysec/ruby-advisory-db/blob/master/gems/devise/CVE-2026-40295.yml"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-601" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-05-08T15:41:47Z",
    "nvd_published_at" : "2026-05-22T20:16:34Z"
  }
}