The Cisco Firewall Services Module (FWSM) is a high-speed, integrated firewall module for Catalyst 6500 series switches and Cisco 7600 series routers. A vulnerability exists in the Cisco Firewall Services Module when URL, FTP, or HTTPS filtering is enabled in which inbound TCP packets can bypass access-list entries intended to explicitly filter them. Cisco has made free software available to address this vulnerability. There are workarounds available to mitigate the effects of the vulnerability. This advisory will be posted at https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20050511-url.