STATUS: Corrected in TPAM 2.5.913
From 2.5.913 Release Notes:
Prevent .exe files from being uploaded to TPAM. BFER 6713
There is also a Hotfix for TPAM version 2.5.904 - 2.5.912:
In TPAM 2.5.913 (or earlier versions after applying the Hotfix); when attempting the upload an executable file, the user will receive the warning: File extension of ".exe" is not allowed for this upload type.