Given my years of experience with Cisco "quality", I'm not surprised by this:

> Another notable affected implementation was the DNSC process in three models of Cisco ethernet switches. In the case where switches had been configured to use 1.1.1.1 these switches experienced spontaneous reboot loops when they received a response containing the reordered CNAMEs.

... but I am surprised by this:

> One such implementation that broke is the getaddrinfo function in glibc, which is commonly used on Linux for DNS resolution.

Not that glibc did anything wrong -- I'm just surprised that anyone is implementing an internet-scale caching resolver without a comprehensive test suite that includes one of the most common client implementations on the planet.