Heap based buffer flow in zlog v1.1.0 to v1.2.17 in zlog_rule_new().The size of record_name is MAXLEN_PATH(1024) + 1 but file_path may have data upto MAXLEN_CFG_LINE(MAXLEN_PATH*4) + 1. So a check was missing in zlog_rule_new() while copying the record_name from file_path + 1 which caused the buffer overflow. An attacker can exploit this vulnerability to overwrite the zlog_record_fn record_func function pointer to get arbitrary code execution or potentially cause remote code execution (RCE).
A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().