In KeePass 2.x before 2.54, it is possible to recover the cleartext master password from a memory dump, even when a workspace is locked or no longer running. The memory dump can be a KeePass process dump, swap file (pagefile.sys), hibernation file (hiberfil.sys), or RAM dump of the entire system. The first character cannot be recovered. In 2.54, there is different API usage and/or random string insertion for mitigation.
KeePass through 2.53 (in a default installation) allows an attacker, who has write access to the XML configuration file, to obtain the cleartext passwords by adding an export trigger. NOTE: the vendor's position is that the password database is not intended to be secure against an attacker who has that level of access to the local PC.
The automatic update feature in KeePass 2.33 and earlier allows man-in-the-middle attackers to execute arbitrary code by spoofing the version check response and supplying a crafted update.