Centrino is not just a processor, it integrates WLAN and other features for laptops. The vulnerabilities are not related to the processor itself but to the wireless features.
The vulnerabilities are pretty awful. The worst of them "could potentially be exploited by attackers within range of the Wi-Fi station to execute arbitrary code on the target system with kernel-level privileges". So at least in theory, somebody could write a WLAN virus that would jump from one laptop to another if the laptops are too close to each other.
Updated to add: What's going on here? To patch one stupid device driver, you need to download a 129MB patch file? Are we missing something here?