Similar to past special-case releases to address security vulnerabilities with NVIDIA's binary blob, the 313.30 driver release officially just contains one security-related fix:
Fixed CVE-2013-0131: NVIDIA UNIX GPU Driver ARGB Cursor Buffer Overflow in "NoScanout" Mode. This buffer overflow, which occurred when an X client installed a large ARGB cursor on an X server running in NoScanout mode, could cause a denial of service (e.g., an X server segmentation fault), or could be exploited to achieve arbitrary code execution.Details on this important NVIDIA driver security bug, which also hit FreeBSD and Solaris OS users, can be found in their customer portal. The good news is that this only affects those using the NoScanOut mode.
This security vulnerability that could take advantage of the X.Org Server generally running as the root user has affected NVIDIA users for a long while -- since the 195.22 driver days, or more easily known as late 2009. This is the first high-profile NVIDIA security driver bug in a few months, but last year they had some issues covered by Michael's NVIDIA Fixes Linux GPU Driver Security Hole and NVIDIA 295.40 Closes High-Risk Security Flaw.
This latest NVIDIA Linux graphics driver can be fetched from NVIDIA.com and is classified as a "certified" Linux GPU driver release.