A vulnerability categorized as critical has been discovered in TOTOLINK A800R 4.1.2cu.5137_B20200730 . Affected by this vulnerability is the function setParentalRules of the file /cgi-bin/cstecgi.cgi of the component firewall.so . Executing a manipulation of the argument urlKeyword can lead to stack-based buffer overflow. This vulnerability is registered as CVE-2026-19815 . It is possible to launch the attack remotely. Furthermore, an exploit is available.