All versions up to V1.1.10P3T18 of ZTE ZXHN F670 product are impacted by heap-based buffer overflow vulnerability, which may allow an attacker to execute arbitrary code.
https://euvd.enisa.europa.eu/vulnerability/EUVD-2018-19091
http://support.zte.com.cn/support/news/LoopholeInfoDetail.aspx?newsId=1009383