CVE-2015-5364 describes a UDP based DoS vulnerability in the Linux kernel that can be used to deny processing cycles to the host operating system and its applications.
A flaw was found in the way the Linux kernel's networking implementation handled UDP packets with incorrect checksum values. A remote attacker could potentially use this flaw to trigger an infinite loop in the kernel, resulting in a denial of service on the system, or cause a denial of service in applications using the edge triggered epoll functionality.
I noticed that Debian released a fix for this, but Redhat still hasn't, and they're classifying this as Important instead of Critical. Important implies that there should be some sort of mitigating factor to the remote exploit, but none of the information I can find has done a good job of explaining what is reducing the risk.
All of this is mildly concerning, but since the internet (or at least Google) isn't on fire I'm forced to assume that Smart Security People aren't terribly concerned. Unfortunately, I'm not as smart as them!
While I'm happy to continue squeezing Redhat for more information (and will update this Q&A if that begins yielding results), I figured that maybe Security.SE could lend a hand here with understanding this. I don't think that routers would be dropping the packets because the bad checksums are in header for the encapsulated protocol, so what prevents this CVE from being a big deal?