DATACOM DB 15.1 PTF LU16040 corrects a Datacom Vulnerability (MFDSA25391), but neither the PTF nor the notification provide any detail about the problem.
You can find additional details about the vulnerability and the solution on the following thread of the CADRE community:
Datacom GA announcement: Close direct access to Datacom LXX files (SECINT PTF # LU16040)