This code was not stolen from Symantec directly but from a foreign government who had the source code, legally, from Symantec.
Part of this theft was that the hackers obtained sourced code for a Symantec product, PC Anywhere.
You could be vulnerable and at risk if you are using Symantec PC Anywhere.
To be safe, update your version of Symantec PC Anywhere, now or completely stop using it. Take it off your computer.
Get more details on this from Symantec, here.