Authentication Services is not directly vulnerable and does not introduce this vulnerability.
Authentication Services uses the operating system provided glibc libraries.
Authentication Services does use the 'gethostbyname*()' set of functions but it uses the operating system provided calls and the information either comes from the operating system or DNS SRV records.
Patching the operating system as described by the Operating System vendor to resolve this issue is not expected to negatively impact Authentication Services.
After patching, the vasd process would need to be restarted however the operating system vendors are generally recommending restarting the machines entirely to ensure the patch is effective.