After actually reading http://breakingmalware.com/injection-techniques/atombombing-brand-new-code-injection-for-windows/ , this isn't a vulnerability per se and doesn't really allow privilege escalation*.
It's a way to inject code into processes (a la WriteProcessMemory/CreateRemoteThread/etc) without getting detected by anti-malware software.
It does however remind me of a classic NT 4 kernel vulnerability in the NtAddAtom function!
* Well, indirectly you could use it to gain more privileges or access to more hosts, as you can use it to hijack a remote desktop session or log terminal sessions, for example. But that's when you have code running as the same user as that process already.