slock 0.9 does not properly handle the XRaiseWindow event when the screen is locked, which might allow physically proximate attackers to obtain sensitive information by pressing a button, which reveals the desktop and active windows.
https://exchange.xforce.ibmcloud.com/vulnerabilities/74666
https://euvd.enisa.europa.eu/vulnerability/EUVD-2012-1630
https://bugzilla.redhat.com/show_bug.cgi?id=786310
https://bugs.gentoo.org/show_bug.cgi?id=401645
http://www.securityfocus.com/bid/52922
http://www.openwall.com/lists/oss-security/2012/04/06/2
http://www.openwall.com/lists/oss-security/2012/04/06/1