The problem can be corrected by upgrading the affected package to version 184.108.40.206-16.19 (for Ubuntu 4.10), or 2.6.10-34.2 (for Ubuntu 5.04). After doing a standard system upgrade you need to reboot your computer to effect the necessary changes.
Alexander Nyberg discovered that ptrace() insufficiently validated addresses on the amd64 platform so that it was possible to set an invalid segment base. A local attacker could exploit this to crash the kernel. This does not affect the i386 and powerpc platforms in any way. (CAN-2005-0756)
Chris Wright discovered that the mmap() function could create illegal memory maps (using the "mmap" function) with the start address pointing beyond the end address. A local user could exploit this to crash the kernel or possibly even execute arbitrary code with kernel privileges. (CAN-2005-1265)