2651XM router using 12.3(9), the vulnerability is fixed in 12.3(9e)
7200VXR router using 12.3(12a)fc3 , fixed is in 12.3(12e)
It would be best if you could just upgrade both to 12.3(16).
if you have a valid CCO, you should be able to download the IOS from the site. You just need to select the platform, the 12.3(16) release and the feature set. The feature set that you will use must be the same as the current feature set.