A vulnerability in the handling of IP fragments for the Cisco Small Business SPA300, SPA500, and SPA51x Series IP Phones could allow an unauthenticated, remote attacker to cause the device to reload unexpectedly, resulting in a denial of service (DoS) condition. The vulnerability is due to the inability to handle many large IP fragments for reassembly in a short duration. An attacker could exploit this vulnerability by sending a crafted stream of IP fragments to the targeted device. An exploit could allow the attacker to cause a DoS condition when the device unexpectedly reloads. Cisco Bug IDs: CSCve82586.

The TFTP implementation on Cisco Small Business SPA30x, SPA50x, SPA51x phones 7.5.7 improperly validates firmware-image file integrity, which allows local users to load a Trojan horse image by leveraging shell access, aka Bug ID CSCut67400.