Added check if the creditcard number string is numeric in validation method isCreditcard in UtilValidate
Isn't this issue related more to accounting (payment processing) or order?
Patch Nils provided have fix for code in framework. That is why I guess chosen component was framework.
This patch looks good and I have also tested it. We can go ahead and commit the patch
Thanks Nils for creating the issue and providing the patch for the same. Thanks Divesh for your help in verification.
Changes are committed in trunk at r1649393.