Buffer Overflow vulnerability in Vigor2620/LTE200 3.9.8.9 and earlier and Vigor2860/2925 3.9.8 and earlier and Vigor2862/2926 3.9.9.5 and earlier and Vigor2133/2762/2832 3.9.9 and earlier and Vigor165/166 4.2.7 and earlier and Vigor2135/2765/2766 4.4.5.1 and earlier and Vigor2865/2866/2927 4.4.5.3 and earlier and Vigor2962/3910 4.3.2.8/4.4.3.1 and earlier and Vigor3912 4.3.6.1 and earlier allows a remote attacker to execute arbitrary code via the CGI parser's handling of the "Content-Length" header of HTTP POST requests.

Certain Draytek products are vulnerable to Cross Site Scripting (XSS) via the wlogin.cgi script and userlogin.cgi script of the router's web application management portal. This affects Vigor3910, Vigor1000B, Vigor2962 v4.3.2.1; Vigor2865 and Vigor2866 v4.4.1.0; Vigor2927 v4.4.2.2; and Vigor2915, Vigor2765, Vigor2766, Vigor2135 v4.4.2.0; Vigor2763 v4.4.2.1; Vigor2862 and Vigor2926 v3.9.9.0; Vigor2925 v3.9.3; Vigor2952 and Vigor3220 v3.9.7.3; Vigor2133 and Vigor2762 v3.9.6.4; and Vigor2832 v3.9.6.2.

The CGI endpoints v2x00.cgi and cgiwcg.cgi of DrayTek Vigor3910 devices through 4.3.2.6 are vulnerable to buffer overflows, by authenticated users, because of missing bounds checking on parameters passed through POST requests to the strncpy function.

Several CGI endpoints are vulnerable to buffer overflows, by authenticated users, because of missing bounds checking on parameters passed through POST requests to the strcpy function on DrayTek Vigor310 devices through 4.3.2.6.

Buffer Overflow vulnerabilities exist in DrayTek Vigor310 devices through 4.3.2.6 (in the Vigor management UI) because of improper retrieval and handling of the CGI form parameters.

DrayTek Vigor3910 devices through 4.3.2.6 have a stack-based overflow when processing query string parameters because GetCGI mishandles extraneous ampersand characters and long key-value pairs.

An issue in DrayTek Vigor310 devices through 4.3.2.6 allows an attacker to obtain sensitive information because the httpd server of the Vigor management UI uses a static string for seeding the PRNG of OpenSSL.

Stored XSS, by authenticated users, is caused by poor sanitization of the Login Page Greeting message in DrayTek Vigor310 devices through 4.3.2.6.

DrayTek Vigor3910 devices through 4.3.2.6 allow unauthenticated DOM-based reflected XSS.

DrayTek Vigor310 devices through 4.3.2.6 allow a remote attacker to execute arbitrary code via the function ftpayloaddns(), because a byte sign-extension operation occurs for the length argument of a memcpy call, leading to a heap-based Buffer Overflow.

An issue was discovered on certain DrayTek Vigor routers before July 2022 such as the Vigor3910 before 4.3.1.1. /cgi-bin/wlogin.cgi has a buffer overflow via the username or password to the aa or ab field.