I enabled proposed, confirmed that as I described in the initial test case gss-server segfaults with 1.12+dfsg-2ubuntu4. Then I installed libgssapi-krb5-2 from trusty-proposed. That pulled in most of the other krb5 packages as I'd expect all version 1.12+dfsg-2ubuntu5.
I ran gss-server and it worked fine. That is, ubuntu5 fixes my problem.
I enabled proposed, confirmed that as I described in the initial test case gss-server segfaults with 1.12+dfsg-2ubuntu4. Then I installed libgssapi-krb5-2 from trusty-proposed. That pulled in most of the other krb5 packages as I'd expect all version 1.12+dfsg-2ubuntu5.
I ran gss-server and it worked fine. That is, ubuntu5 fixes my problem.