[CentOS] how to get erratas's summary and URL with "check-update" ?

Hello,

running a "yum check-update" is cool to get a list of packages to
update with versions. In addition of that, i'm looking for a way to get
for each package, the link to the RH's errata and the severity status in
the same report.

My idea was to parse output of check-update, and join it with
"centos-announce" mailing list subjects to get it. It's pretty twisted.

RHN interface offer a similar report, but it's web based,
authenticated, and co ...

Is anyone has ever thought about it ? 

-- 
Martin