An exploitable integer overflow vulnerability exists in the PlanMaker document parsing functionality of SoftMaker Office 2021’s PlanMaker application. A specially crafted document can cause the document parser perform arithmetic that may overflow which can result in an undersized heap allocation. Later when copying data from the file into this allocation, a heap-based buffer overflow will occur which can corrupt memory. These types of memory corruptions can allow for code execution under the context of the application. An attacker can entice the victim to open a document to trigger this vulnerability.