CVE-2023-20215: Cisco Asyncos

Medium severity, CVSS 5.3. EPSS: 0.6% chance of exploitation in the next 30 days.

A vulnerability in the scanning engines of Cisco AsyncOS Software for Cisco Secure Web Appliance could allow an unauthenticated, remote attacker to bypass a configured rule, allowing traffic onto a network that should have been blocked. This vulnerability is due to improper detection of malicious traffic when the traffic is encoded with a specific content format. An attacker could exploit this vulnerability by using an affected device to connect to a malicious server and receiving crafted HTTP responses. A successful exploit could allow the attacker to bypass an explicit block rule and receive traffic that should have been rejected by the device.

Affected products

• Cisco Asyncos: version 11.7.0-406 only; version 11.7.0-418 only; version 11.7.1-006 only; version 11.7.1-020 only; version 11.7.1-049 only; version 11.7.2-011 only; …

Published 2023-08-03. Last modified 2026-06-17.