The kdenetwork packages contain networking applications for the K DesktopEnvironment (KDE). Krfb Desktop Sharing, which is a part of the kdenetworkpackage, is a server application that allows session sharing between users.Krfb uses the LibVNCServer library.A NULL pointer dereference flaw was found in the way LibVNCServer handledcertain ClientCutText message. A remote attacker could use this flaw tocrash the VNC server by sending a specially crafted ClientCutText messagefrom a VNC client. (CVE-2014-6053)A divide-by-zero flaw was found in the way LibVNCServer handled the scalingfactor when it was set to "0". A remote attacker could use this flaw tocrash the VNC server using a malicious VNC client. (CVE-2014-6054)Two stack-based buffer overflow flaws were found in the way LibVNCServerhandled file transfers. A remote attacker could use this flaw to crash theVNC server using a malicious VNC client. (CVE-2014-6055)Red Hat would like to thank oCERT for reporting these issues. oCERTacknowledges Nicolas Ruff as the original reporter.Note: Prior to this update, the kdenetwork packages used an embedded copyof the LibVNCServer library. With this update, the kdenetwork packages havebeen modified to use the system LibVNCServer packages. Therefore, theupdate provided by RHSA-2014:1826 must be installed to fully address theissues in krfb described above.All kdenetwork users are advised to upgrade to these updated packages,which contain backported patches to correct these issues. All runninginstances of the krfb server must be restarted for this update to takeeffect.