Cisco CSS 11500 Series Content Services Switches configured for Hyper Text Transfer Protocol (HTTP) compression are vulnerable to a Denial of Service (DoS) attack when processing valid, but obsolete, or specially crafted HTTP request. Cisco has made free software available to address this vulnerability for affected customers. The workaround is to disable HTTP compression. This advisory is posted at https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20060405-css.