The check which introduced the bug for cve-2012-1016 was brought in when
pkinit agility was introduced, upstream's commit
3725d22140c23a376dd79b69d130be8e2b91005f on 19 Sept 2011. The first
release to include this code was krb5-1.10; the 1.8 version in squeeze is
too old for this bug.