The auth-proxy functionality in Cisco Firewall Services Module (FWSM) software 3.1 and 3.2 before 3.2(20.1), 4.0 before 4.0(15.2), and 4.1 before 4.1(5.1) allows remote attackers to cause a denial of service (device reload) via a crafted URL, aka Bug ID CSCtg02624.
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20130410-fwsm