Security updates for the X Window System client libraries
If you see a bunch of X.org packages upgrades pending in your Squeeze or brand new Wheezy system, don't panic!
Ilja van Sprundel, a security researcher from IOActive, has discovered a large number of issues in the various X client libraries and he has worked with X.Org's security team to analyze, confirm, and fix these issues. You can find more information in the security advisory from X.org.
The Debian Security and X.org teams have quickly updated all the affected packages in Squeeze and Wheezy. You can see the full list of updates in the debian-security-announce mailing list archives.