Yii2 weak secret key
Description
Each Yii2 web application contains a secret key which used to sign cookies for protection against cookie data tampering. It's very important that an attacker doesn't know the value of this secret key. Your application is using a weak/known secret key and Invicti managed to guess this key.
Remediation
Change the value of the secret "cookieValidationKey" to a long random string.