I am no longer able to do a routine "yum update" due to two packages that
require newer versions of their dependencies than are available in SL repos.
Package cryptsetup-luks-libs was causing problem since the beginning of
August, and openldap started in last week or so. I have repos sl,
sl-security and sl-fastbugs enabled, and the system is fully updated, apart
from the offending packages.

yum output:

Setting up Update Process
Resolving Dependencies
--> Running transaction check
---> Package cryptsetup-luks.x86_64 0:1.2.0-3.el6_1.2 set to be updated
---> Package cryptsetup-luks-libs.x86_64 0:1.2.0-3.el6_1.2 set to be updated
--> Processing Dependency: device-mapper-libs >= 1.02.61 for package:
cryptsetup-luks-libs-1.2.0-3.el6_1.2.x86_64
---> Package openldap.x86_64 0:2.4.23-15.el6_1.1 set to be updated
--> Processing Dependency: libnss3.so(NSS_3.12.9)(64bit) for package:
openldap-2.4.23-15.el6_1.1.x86_64
--> Finished Dependency Resolution
Error: Package: cryptsetup-luks-libs-1.2.0-3.el6_1.2.x86_64 (sl-fastbugs)
           Requires: device-mapper-libs >= 1.02.61
           Installed: device-mapper-libs-1.02.53-8.el6_0.4.x86_64 (@sl-fastbugs)
               device-mapper-libs = 1.02.53-8.el6_0.4
           Available: device-mapper-libs-1.02.53-8.el6.i686 (sl)
               device-mapper-libs = 1.02.53-8.el6
           Available: device-mapper-libs-1.02.53-8.el6.x86_64 (sl)
               device-mapper-libs = 1.02.53-8.el6
Error: Package: openldap-2.4.23-15.el6_1.1.x86_64 (sl-fastbugs)
           Requires: libnss3.so(NSS_3.12.9)(64bit)
 You could try using --skip-broken to work around the problem
 You could try running: rpm -Va --nofiles --nodigest

uname -a
Linux xxx.xxx.xxx 2.6.32-131.12.1.el6.x86_64 #1 SMP Tue Aug 23 11:13:45 CDT
2011 x86_64 x86_64 x86_64 GNU/Linux