Grandstream HT800 series firmware version 1.0.17.5 and below is vulnerable to CPU exhaustion due to an infinite loop in the TR-069 service. Unauthenticated remote attackers can trigger this case by sending a one character TCP message to the TR-069 service.
The Grandstream BudgeTone 200 IP phone, with program 1.1.1.14 and bootloader 1.1.1.5, allows remote attackers to cause a denial of service (device crash) via SIP (1) INVITE, (2) CANCEL, or unspecified other messages with a WWW-Authenticate header containing a crafted Digest domain.
The Grandstream HT-488 0.1 allows remote attackers to cause a denial of service (device crash) via a flood of fragmented packets to port 5060.