This vulnerability exists in Meon KYC solutions due to improper handling of access and refresh tokens in certain API endpoints of authentication process. A remote attacker could exploit this vulnerability by intercepting and manipulating the responses through API request body leading to unauthorized access of other user accounts.
Authenticating a user, or otherwise establishing a new user session, without invalidating any existing session identifier gives an attacker the opportunity to steal authenticated sessions.
Such a scenario is commonly observed when:
In the generic exploit of session fixation vulnerabilities, an attacker creates a new session on a web application and records the associated session identifier. The attacker then causes the victim to associate, and possibly authenticate, against the server using that session identifier, giving the attacker access to the user’s account through the active session.