A Heap Buffer Overflow exists in GNU Tar 1.34. The issue takes place at from_header() in list.c in the tar application. The issue occurs when attempting to read files with old V7 tar format with an especially crafted checksum.
As a result, an invalid memory read that leads to a conditional jump or move operation on uninitialised memory values takes place. Exploitation of this issue leads to code execution or DOS attacks and could potentially result in other memory-related issues.