The affected software was last shipped with new units in early 1997. Catalyst 12xx family, up through software version 4.29.
Fixes are available for both bugs.
The fixes have been in the field for some time. Most Catalyst switch users have probably already installed the fixes. Catalyst 2926 switches are not affected, because the Catalyst 2926 was not released until after the software fix was made. Catalyst 2900XL switches run unrelated software, and are not affected by this vulnerability. Catalyst 12xx switches running versions 4.30 and later are not affected.