The dvb_ca_ioctl function in drivers/media/dvb/ttpci/av7110_ca.c in the Linux kernel before 2.6.38-rc2 does not check the sign of a certain integer field, which allows local users to cause a denial of service (memory corruption) or possibly have unspecified other impact via a negative value.
Improper Restriction of Operations within the Bounds of a Memory Buffer The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary.