A vulnerability marked as critical has been reported in TOTOLINK A800R 4.1.2cu.5137_B20200730 . This impacts the function setUrlFilterRules of the file /cgi-bin/cstecgi.cgi of the component firewall.so . The manipulation of the argument url leads to stack-based buffer overflow. This vulnerability is documented as CVE-2026-19846 . The attack can be initiated remotely. Additionally, an exploit exists.