The SIP implementation on the Cisco PGW 2200 Softswitch with software 9.7(3)S before 9.7(3)S9 and 9.7(3)P before 9.7(3)P9 allows remote attackers to cause a denial of service (device crash) via a malformed header, aka Bug ID CSCsk04588.
Improper Input Validation The product receives input or data, but it does
not validate or incorrectly validates that the input has the
properties that are required to process the data safely and
correctly.