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CVE-2026-40295 medium CVSS 6.1

Open Redirect in devise (CVE-2026-40295)

Summary

Vulnerability in devise (CVE-2026-40295). Risk of unauthorized operations or information disclosure. Exploitable via Referer header. Mitigation: upgrade to 5.0.4 or later.

Original description

The description as published by the source.

Summary

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.

Details

The vulnerable code is in lib/devise/failure_app.rb:

def redirect_url
  if warden_message == :timeout
    flash[:timedout] = true if is_flashing_format?

    path = if request.get?
      attempted_path          # safe: server-side value from warden options
    else
      request.referrer        # UNSAFE: HTTP Referer header, attacker-controlled
    end

    path || scope_url
  else
    scope_url
  end
end

This is passed directly to redirect_to:

def redirect
  store_location!
  # ...
  redirect_to redirect_url   # redirect_url may be an external attacker URL
end

The 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 r…

Source: GitHub Security Advisories (Global) NVD GitHub Advisory

Auto-generated summary

Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.

A vulnerability tracked as CVE-2026-40295 has been found in devise.
Attackers can target a specific entry point like Referer header over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 6.1/10.
What to do: upgrade devise to 5.0.4 or later.
If unsure, ask your IT team or search "devise CVE-2026-40295" on the vendor's site.

CVE-2026-40295 (devise) — CWE-601 / CVSS v3 6.1
Attack vector: remote (network-reachable) / unauthenticated
Attack surface: Referer header / Timeoutable / request.referrer / Referer
Patched: 5.0.4 — apply immediately
Workaround: None beyond upgrading.
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.

❓ What is the problem

A vulnerability (CWE-601) exists in devise. Attackers reach the vulnerable code path via Referer header without authentication.

📍 Affected scope

Check the vendor advisory for the affected versions of devise. Attack surface: Referer header / Timeoutable / request.referrer / Referer.

🔥 Severity

Severity: Medium (CVSS 6.1/10). Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to 5.0.4.

🛡️ Workaround

Workaround: None beyond upgrading.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'devise' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

  1. 1
    Identify exposure identify 
    grep -r 'devise' . | grep -v node_modules

    リポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で devise を grep し、稼働しているサービス・バージョンを把握する。

  2. 2
    Apply temporary workaround mitigate 
    None beyond upgrading.

    パッチが適用されるまでの応急処置として、None beyond upgrading. を実施。回避策の副作用 (機能低下) を確認した上で。

  3. 3
    Apply patch patch 
    Upgrade devise to 5.0.4

    ステージング環境で 5.0.4 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。

  4. 4
    Post-deployment verification verify 
    Confirm patched version is live in production

    パッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。

Affected packages

rubygems devise
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"5.0.4"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

References

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