According to ZDNet, Cisco has issued a warning about multiple security flaws in some of its Wireless LAN controllers.
If you have Cisco Wireless LAN Controllers (WLCs), Cisco Catalyst 6500 Wireless Services Modules (WiSMs) or Cisco Catalyst 3750 Integrated Wireless LAN Controllers, pay attention. The four vulnerabilities could lead to DoS or privilege escalation attacks. A flaw only involving WLC software version 18.104.22.168 could give a restricted user full administrative rights and should be treated as a "high priority" update.
According to the advisory, there are no workarounds available.