A stack-based buffer overflow exists in the httpd binary of Linksys E1200 v2 routers (Firmware E1200_v2.0.11.001_us.tar.gz). The apply_cgi and block_cgi functions copy user-supplied input from the "url" CGI parameter into stack buffers (v36, v29) using sprintf without bounds checking. Because these buffers are allocated as single-byte variables, any non-empty input will trigger a buffer overflow. Remote attackers can exploit this vulnerability via crafted HTTP requests to execute arbitrary code or cause denial of service without authentication.