There’s a recently talked about bug in SYSRET that apparently affects a lot of operating systems, including Linux and several BSDs. It looks like DragonFly is not affected, but Matthew Dillon has put in changes just in case.
A running description of activity related to DragonFly BSD.
From the document you link to:
“OpenBSD and Linux were not vulnerable. Linux actually fixed the bug in 2006, with CVE-2006-0744.”
Yes, and?