DBLTek GoIP-1 firmware versions up to and including GHSFVT-1.1-67-5 contain a local file inclusion vulnerability. The device's web server exposes handlers (frame.html and frame.A100.html) that accept a path parameter (content or sidebar) which is not properly validated or canonicalized. An attacker can supply directory-traversal sequences to cause the server to read and return arbitrary filesystem files that the webserver user can access. Other GoIP models and firmware versions are likely affected. Exploitation evidence was observed by the Shadowserver Foundation on 2024-03-21 UTC.

DBLTek GoIP devices (models GoIP 1, 4, 8, 16, and 32) contain an undocumented vendor backdoor in the Telnet administrative interface that allows remote authentication as an undocumented user via a proprietary challenge–response scheme which is fundamentally flawed. Because the challenge response can be computed from the challenge itself, a remote attacker can authenticate without knowledge of a secret and obtain a root shell on the device. This can lead to persistent remote code execution, full device compromise, and arbitrary control of the device and any managed services. The firmware used within these devices was updated in December 2016 to make this vulnerability more complex to exploit. However, it is unknown if DBLTek has taken steps to fully mitigate.

The web server on DBL DBLTek devices allows remote attackers to execute arbitrary OS commands by obtaining the admin password via a frame.html?content=/dev/mtdblock/5 request, and then using this password for the HTTP Basic Authentication needed for a changepassword.csp request, which supports a "<%%25call system.exec:" string in the passwd parameter.