A Heap Overflow (Remote Code Execution) issue was discovered in Design Science MathType 6.9c. Crafted input can modify the next pointer of a linked list. This is fixed in 6.9d.
CWE-787 - Out-of-Bounds Write
Out-of-bounds write vulnerability is a memory access bug that allows software to write data past the end or before the beginning of the intended buffer. This may result in the corruption of data, a crash, or arbitrary code execution.