Cross-site scripting in the Web Administration interface of Network Optix Nx Witness VMS before version 6.1.3 on Linux, Windows and MacOS allows an adjacent-network attacker to execute arbitrary JavaScript in the browser of an authenticated administrator and steal the administrator's session token, resulting in Administrator Account Takeover. An attacker who controls an Nx server on the same network segment can set that server's site name to a script payload, which executes when an administrator opens the "Merge with Another Site" dialog and the site selection list is displayed.Solution: Update to Nx Witness VMS version 6.1.3 or later.