heartcombo devise up to 5.0.2 Confirmable confirmation_token/unconfirmed_email race condition

Summaryinfo

A vulnerability, which was classified as problematic, was found in heartcombo devise up to 5.0.2. Affected by this vulnerability is an unknown functionality of the component Confirmable Module. Such manipulation of the argument confirmation_token/unconfirmed_email leads to race condition. This vulnerability is documented as CVE-2026-32700. The attack can be executed remotely. There is not any exploit available. You should upgrade the affected component.

Detailsinfo

A vulnerability was found in heartcombo devise up to 5.0.2 and classified as problematic. Affected by this issue is some unknown functionality of the component Confirmable Module. The manipulation of the argument confirmation_token/unconfirmed_email with an unknown input leads to a race condition vulnerability. Using CWE to declare the problem leads to CWE-362. The product contains a code sequence that can run concurrently with other code, and the code sequence requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence that is operating concurrently. Impacted is confidentiality, integrity, and availability. CVE summarizes:

Devise is an authentication solution for Rails based on Warden. Prior to version 5.0.3, 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. This is patched in Devise v5.0.3. Users should upgrade as soon as possible. As a workaround, applications can override a specific method from Devise models to force `unconfirmed_email` to be persisted when unchanged. Note that Mongoid does not seem to respect that `will_change!` should force the attribute to be persisted, even if it did not really change, so the user might have to implement a workaround similar to Devise by setting `changed_attributes["unconfirmed_email"] = nil` as well.

The advisory is available at github.com. This vulnerability is handled as CVE-2026-32700 since 03/13/2026. The exploitation is known to be difficult. The attack may be launched remotely. Technical details are known, but there is no available exploit.

The vulnerability scanner Nessus provides a plugin with the ID 303072 (Linux Distros Unpatched Vulnerability : CVE-2026-32700), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 5.0.3 eliminates this vulnerability. Applying a patch is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at Tenable (303072). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Vendor

• heartcombo

Name

• devise

Version

• 5.0.0
• 5.0.1
• 5.0.2

Website

• Product: https://github.com/heartcombo/devise/

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If you want to get best quality of vulnerability data, you may have to visit VulDB.

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