Symantec has updated their advisory (http://www.symantec.com/avcenter/security/Content/2006.05.25.html)

They confirm that the following versions are affected:
Symantec Client Security-
   3.0 all builds
   3.1 all builds
Symantec Antivirus Corporate Edition-
   10.0 all builds
   10.1 all builds

The following patches are available:
Symantec Client Security-
   3.0 Builds 3.0.2.2010 and 3.0.2.2020
   3.1 Builds 3.1.0.394 and 3.1.0.400

Symantec Antivirus Corporate Edition-
   10.0 Builds 10.0.2.2010 and 10.0.2.2020
   10.1 Builds 10.1.0.394 and 10.1.0.400

Symantec recommends that you upgrade to a "patchable" version.  This may be bad news for some organizations.

Some have reported that the patching process is not trivial, and can be difficult to roll out in some environments.

At this time, there have been no reports of proof-of-concept-code or exploit code other than that held privately by eEye.

We have not received any reports of exploitation in the wild.