Exposure of Sensitive Information to an Unauthorized Actor
The OpenConnectionTask::handleStateHelper function in Imap/Tasks/OpenConnectionTask.cpp in Trojita before 0.4.1 allows man-in-the-middle attackers to trigger use of cleartext for saving a message into a (1) sent or (2) draft folder via a PREAUTH response that prevents later use of the STARTTLS command.
CWE-200 - Information Exposure
An information exposure vulnerability is categorized as an information flow (IF) weakness, which can potentially allow unauthorized access to otherwise classified information in the application, such as confidential personal information (demographics, financials, health records, etc.), business secrets, and the application's internal environment.