Devise has an Open Redirect via Unvalidated request.referrer in Timeoutable Session Timeout Handler

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

6.1 · CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

EPSS

• CVE-2026-40295: 0.24% estimated exploitation activity in the next 30 days; percentile 15.30 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary When the Timeoutable module is enabled in Devise, the FailureApp#redirecturl 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 attemptedpath) and Devise's own storelocationfor mechanism (which strips external hosts via extractpathfromlocation), both of which are protected; only the non-GET timeout redirect path is unprotected. Details The vulnerable code is in lib/devise/failureapp.rb: This is passed directly to redirectto: The GET timeout path uses attemptedpath, which is set server-side by Warden and cannot be influenced by the client. The storelocation! method also only runs for GET requests, so no session-based protection is…

Published by the source

8 May 2026, 15:41 UTC

Last modified by the source

29 May 2026, 21:44 UTC

Source last checked

26 Oct 2026, 15:52 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-jp94-3292-c3xv

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# Patch Next advisory brief: CVE-2026-40295

Advisory: Devise has an Open Redirect via Unvalidated `request.referrer` in Timeoutable Session Timeout Handler
IDs: CVE-2026-40295, GHSA-jp94-3292-c3xv
Record: https://patchnext.com/advisories/cve-2026-40295 (revision 1, source checked 26 Oct 2026, 15:52 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: devise 5.0.4. A vendor fix does not mean a deployment is fixed.

## Affected components
- RubyGems devise: affected <= 5.0.3; fixed in 5.0.4

## Suggested inspection (read-only)
- RubyGems devise: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on devise.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-jp94-3292-c3xv (GitHub-reviewed advisory GHSA-jp94-3292-c3xv lists affected ranges: RubyGems devise >=0 <=5.0.3)

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