CRMEB OutAccountServices.php testOutUrl server-side request forgery

A security vulnerability has been detected in CRMEB up to 5.6.1. The impacted element is the function testOutUrl of the file app/services/out/OutAccountServices.php. The manipulation of the argument push_token_url leads to server-side request forgery. Remote exploitation of the attack is possible. The exploit has been disclosed publicly and may be used. The vendor was contacted early about this disclosure but did not respond in any way.