Cisco AsyncOS before 8.5.7-043, 9.x before 9.1.1-023, and 9.5.x and 9.6.x before 9.6.0-046 on Email Security Appliance (ESA) devices mishandles malformed fields during body-contains, attachment-contains, every-attachment-contains, attachment-binary-contains, dictionary-match, and attachment-dictionary-match filtering, which allows remote attackers to cause a denial of service (memory consumption) via a crafted attachment in an e-mail message, aka Bug ID CSCuv47151.

A vulnerability in the email message filtering feature of Cisco AsyncOS Software for Cisco Email Security Appliances could allow an unauthenticated, remote attacker to cause an affected device to stop scanning and forwarding email messages due to a denial of service (DoS) condition. Affected Products: This vulnerability affects all releases prior to the first fixed release of Cisco AsyncOS Software for Cisco Email Security Appliances, both virtual and hardware appliances, if the software is configured to apply a message filter or content filter to incoming email attachments. The vulnerability is not limited to any specific rules or actions for a message filter or content filter. More Information: CSCuz63143. Known Affected Releases: 8.5.7-042 9.7.0-125. Known Fixed Releases: 10.0.0-125 9.1.1-038 9.7.2-047.

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.

A vulnerability in the Multipurpose Internet Mail Extensions (MIME) scanner of Cisco AsyncOS Software for Cisco Email Security Appliances (ESA) and Web Security Appliances (WSA) could allow an unauthenticated, remote attacker to bypass configured user filters on the device. Affected Products: all releases prior to the first fixed release of Cisco AsyncOS Software for Cisco ESA and Cisco WSA, both virtual and hardware appliances, if the software is configured with message or content filters to scan incoming email attachments. More Information: CSCuw03606, CSCux59734. Known Affected Releases: 8.0.0-000 8.5.6-106 9.0.0-000 9.1.0-032 9.6.0-042 9.5.0-444 WSA10.0.0-000. Known Fixed Releases: 9.1.1-038 9.7.1-066.