CVE-2020-26254

omniauth-apple allows attacker to fake their email address during authentication

Workarounds

If unable to upgrade to a patched version, monkey patching OmniAuth::Strategies::Apple#email as follows is advised as a workaround:

module OmniAuth
  module Strategies
    class Apple
      def email
        id_info['email']
      end
    end
  end
end

This vulnerability impacts applications using the omniauth-apple strategy of OmniAuth and using the info.email field of OmniAuth's Auth Hash Schema for any kind of identification. The value of this field may be set to any value of the attacker's choice including email addresses of other users.

For example, an application using omniauth-apple with the following code will be impacted:

def omniauth_callback
    auth_hash = request.env['omniauth.auth']
    @authenticated_user = User.find_by(email: auth_hash.info.email)
end

Applications not using info.email for identification but are instead using the uid field are not impacted in the same manner. Note, these applications may still be negatively affected if the value of info.email is being used for other purposes.

CVE-2020-26254 has a CVSS score of 7.7 (High). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.0.1); upgrading removes the vulnerable code path.

Kodem intelligence

Already deployed Kodem?

Applications using affected versions of omniauth-apple are advised to upgrade to omniauth-apple version 1.0.1 or later.

1. What is CVE-2020-26254? CVE-2020-26254 is a high-severity security vulnerability in omniauth-apple (rubygems), affecting versions < 1.0.1. It is fixed in 1.0.1.
2. How severe is CVE-2020-26254? CVE-2020-26254 has a CVSS score of 7.7 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of omniauth-apple are affected by CVE-2020-26254? omniauth-apple (rubygems) versions < 1.0.1 is affected.
4. Is there a fix for CVE-2020-26254? Yes. CVE-2020-26254 is fixed in 1.0.1. Upgrade to this version or later.
5. Is CVE-2020-26254 exploitable, and should I be worried? Whether CVE-2020-26254 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2020-26254 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2020-26254? Upgrade omniauth-apple to 1.0.1 or later.