rxvt-unicode - security update

Phillip Hallam-Baker discovered that window property values could be
queried in rxvt-unicode, resulting in the potential execution of
arbitrary commands.

For the oldstable distribution (squeeze), this problem has been fixed in
version 9.07-2+deb6u1.

For the stable distribution (wheezy), this problem has been fixed in
version 9.15-2+deb7u1.

For the testing distribution (jessie), this problem has been fixed in
version 9.20-1.

For the unstable distribution (sid), this problem has been fixed in
version 9.20-1.

We recommend that you upgrade your rxvt-unicode packages.