The Grandstream UCM Series IP PBX before firmware version 1.0.20.52 is affected by a parameter injection vulnerability in the HTTP interface. A remote and authenticated attacker can execute arbitrary code by sending a crafted HTTP request. Authentication may be possible using a default user and password. Affected models are the UCM6202, UCM6204, UCM6208, and UCM6510.

An os command injection vulnerability exists in the CWMP SelfDefinedTimeZone functionality of Grandstream GXP2135 1.0.9.129, 1.0.11.74 and 1.0.11.79. A specially crafted network packet can lead to arbitrary command execution. An attacker can send a sequence of malicious packets to trigger this vulnerability.

In Grandstream GSD3710 in its 1.0.11.13 version, it's possible to overflow the stack since it doesn't check the param length before using the sscanf instruction. Because of that, an attacker could create a socket and connect with a remote IP:port by opening a shell and getting full access to the system. The exploit affects daemons dbmng and logsrv that are running on ports 8000 and 8001 by default.

an attacker with knowledge of user/pass of Grandstream GSD3710 in its 1.0.11.13 version, could overflow the stack since it doesn't check the param length before use the strcopy instruction. The explotation of this vulnerability may lead an attacker to execute a shell with full access.

Multiple buffer overflows in the limited configuration shell (/sbin/gs_config) on Grandstream HT801 devices before 1.0.29 allow remote authenticated users to execute arbitrary code as root via a crafted manage_if setting, thus bypassing the intended restrictions of this shell and taking full control of the device. There are default weak credentials that can be used to authenticate.

An issue was discovered on the Grandstream HT801 Analog Telephone Adaptor before 1.0.29.8. From the limited configuration shell, it is possible to set the malicious gdb_debug_server variable. As a result, after a reboot, the device downloads and executes malicious scripts from an attacker-defined host.

Grandstream GRP261x VoIP phone running firmware version 1.0.3.6 (Base) allow Authentication Bypass in its administrative web interface.

Grandstream GRP261x VoIP phone running firmware version 1.0.3.6 (Base) allows Command Injection as root in its administrative web interface.

Grandstream HT800 series firmware version 1.0.17.5 and below is vulnerable to an OS command injection vulnerability. Unauthenticated remote attackers can execute arbitrary commands as root by crafting a special configuration file and sending a crafted SIP message.

Grandstream HT800 series firmware version 1.0.17.5 and below contain a backdoor in the SSH service. An authenticated remote attacker can obtain a root shell by correctly answering a challenge prompt.