A vulnerability was found in TOTOLINK A800R 4.1.2cu.5137_B20200730 . It has been classified as critical . This affects the function UploadCustomModule of the file /cgi-bin/cstecgi.cgi of the component product.so . This manipulation of the argument File causes stack-based buffer overflow. This vulnerability is tracked as CVE-2026-19812 . The attack is possible to be carried out remotely. Moreover, an exploit is present.