A vulnerability in the proxy engine of the Cisco Web Security Appliance (WSA) could allow an unauthenticated, remote attacker to bypass security restrictions.
The vulnerability is due to improper handling of malformed HTTP methods. An attacker could exploit this vulnerability by crafting an improper HTTP method. A successful exploit could allow the attacker to circumvent WSA functionality that prevents proxied network traffic.
Cisco released software updates that address this vulnerability. There are no workarounds that mitigate this vulnerability.
This advisory is available at the following link: http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20160119-wsa