A session fixation vulnerability has been identified in osTicket v1.18.2. This security flaw allows an attacker to hijack a victim’s account by keeping the initial session identifier (OSTSESSID) active after a successful login.

The issue lies in the fact that the application does not invalidate the pre-authentication cookie or generate a new identifier for the authenticated context. As a result, if an attacker manages to set a known session identifier in the victim’s browser, they will be able to maintain unauthorised access to the account once the victim has authenticated.