Vladimir Kononovich, a Security Researcher has found a flaw that allows for a remote code execution on the DVR. An attacker could inject malicious HTTP headers into request packets to execute arbitrary code. The manufacturer has released patch firmware for the flaw, please refer to the manufacturer's report for details and workarounds.
A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function).