A vulnerability in the web proxy functionality of Cisco AsyncOS Software for Cisco Web Security Appliances could allow an unauthenticated, remote attacker to exhaust system memory and cause a denial of service (DoS) condition on an affected system. The vulnerability exists because the affected software improperly manages memory resources for TCP connections to a targeted device. An attacker could exploit this vulnerability by establishing a high number of TCP connections to the data interface of an affected device via IPv4 or IPv6. A successful exploit could allow the attacker to exhaust system memory, which could cause the system to stop processing new connections and result in a DoS condition. System recovery may require manual intervention. Cisco Bug IDs: CSCvf36610.

A vulnerability in the URL filtering feature of Cisco AsyncOS Software for Cisco Web Security Appliance (WSA) could allow an unauthenticated, remote attacker to bypass a configured URL filter rule. Affected Products: This vulnerability affects all releases prior to the first fixed release of Cisco AsyncOS Software for Cisco Web Security Appliance (WSA), both virtual and hardware appliances, that are configured with URL filters for email scanning. More Information: CSCvc69700. Known Affected Releases: 8.5.3-069 9.1.1-074 9.1.2-010.

A vulnerability in HTTP URL parsing of Cisco AsyncOS for Cisco Web Security Appliance (WSA) could allow an unauthenticated, remote attacker to cause a denial of service (DoS) vulnerability due to the proxy process unexpectedly restarting. More Information: CSCvb04312. Known Affected Releases: 9.0.1-162 9.1.1-074. Known Fixed Releases: 10.1.0-129 9.1.2-010.

A vulnerability in the Decrypt for End-User Notification configuration parameter of Cisco AsyncOS Software for Cisco Web Security Appliances could allow an unauthenticated, remote attacker to connect to a secure website over Secure Sockets Layer (SSL) or Transport Layer Security (TLS), even if the WSA is configured to block connections to the website. Affected Products: This vulnerability affects Cisco Web Security Appliances if the HTTPS decryption options are enabled and configured for the device to block connections to certain websites. More Information: CSCvb49012. Known Affected Releases: 9.0.1-162 9.1.1-074.

A vulnerability in the email message and content filtering for malformed Multipurpose Internet Mail Extensions (MIME) headers of Cisco AsyncOS Software for Cisco Email Security Appliances (ESA) and Web Security Appliances (WSA) could allow an unauthenticated, remote attacker to bypass the filtering functionality of the targeted device. Emails that should have been quarantined could instead be processed. Affected Products: This vulnerability affects all releases prior to the first fixed release of Cisco AsyncOS Software for Cisco ESA and Cisco WSA on both virtual and hardware appliances that are configured with message or content filters to scan incoming email attachments. More Information: CSCuy54740, CSCuy75174. Known Affected Releases: 9.7.1-066 9.5.0-575 WSA10.0.0-000. Known Fixed Releases: 10.0.0-125 9.1.1-038 9.7.2-047.