Details

Impact

A race condition in Devise's Confirmable module allows an attacker to confirm an email address they do not own. This affects any Devise application using the reconfirmable option (the default when using Confirmable with email changes).

By sending two concurrent email change requests, an attacker can desynchronize the confirmation_token and unconfirmed_email fields. The confirmation token is sent to an email the attacker controls, but the unconfirmed_email in the database points to a victim's email address. When the attacker uses the token, the victim's email is confirmed on the attacker's account.

Patches

This is patched in Devise v5.0.3. Users should upgrade as soon as possible.

Workarounds

Applications can override this specific method from Devise models to force unconfirmed_email to be persisted when unchanged: (assuming your model is User)

class User < ApplicationRecord
  protected

  def postpone_email_change_until_confirmation_and_regenerate_confirmation_token
    unconfirmed_email_will_change!
    super
  end
end

Note: Mongoid does not seem to respect that will_change! should force the attribute to be persisted, even if it did not really change, so you might have to implement a workaround similar to Devise by setting changed_attributes["unconfirmed_email"] = nil as well.

Severity

• CVSS Score: 6.0 / 10 (Medium)
• Vector String: CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

References

• https://github.com/heartcombo/devise/security/advisories/GHSA-57hq-95w6-v4fc
• https://github.com/heartcombo/devise/issues/5783
• https://github.com/heartcombo/devise/pull/5784
• https://github.com/rubysec/ruby-advisory-db/blob/master/gems/devise/GHSA-57hq-95w6-v4fc.yml
• https://nvd.nist.gov/vuln/detail/CVE-2026-32700
• https://github.com/rubysec/ruby-advisory-db/blob/master/gems/devise/CVE-2026-32700.yml
• https://github.com/advisories/GHSA-57hq-95w6-v4fc

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

v5.0.3

Compare Source

• security fixes
  • Fix race condition vulnerability on confirmable "change email" which would allow confirming an email they don't own CVE-2026-32700 #​5783 #​5784

v5.0.2

Compare Source

• enhancements
  • Allow resource class scopes to override the global configuration for sign_in_after_change_password behaviour. #​5825
    • Note: some users ran into an issue with this change because RegistrationsController now relies on a setting from the :registerable module. These users were configuring their own routes pointing to the RegistrationsController for resource edit/update actions mostly, without relying on the other registration actions (e.g. user sign up.), so they omitted :registerable from the model declaration. While using just a portion of the controller functionality is a valid use for :registerable (or any module really), the module must still be declared in the model, much like the other modules must be declared if you plan on using just a portion of their behavior. Please check this issue for more info.
  • Add sign_in_after_reset_password? check hook to passwords controller, to allow it to be customized by users. #​5826

v5.0.1

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• bug fixes
  • Fix translation issue with German E-Mail on invalid authentication messages caused by previous fix for incorrect grammar #​5822