CVE-2019-1886: Cisco Asyncos

High severity, CVSS 8.6. EPSS: 1.3% chance of exploitation in the next 30 days.

A vulnerability in the HTTPS decryption feature of Cisco Web Security Appliance (WSA) could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition. The vulnerability is due to insufficient validation of Secure Sockets Layer (SSL) server certificates. An attacker could exploit this vulnerability by installing a malformed certificate in a web server and sending a request to it through the Cisco WSA. A successful exploit could allow the attacker to cause an unexpected restart of the proxy process on an affected device.

Affected products

• Cisco Asyncos: from 10.5, before 10.5.5-005 (fixed in 10.5.5-005); from 11.5, before 11.5.2-020 (fixed in 11.5.2-020)
• Cisco Web Security Appliance: version 10.5.2-072 only; version 10.5.3-025 only; version 11.7.0-fcs-334 only

Published 2019-07-04. Last modified 2026-06-17.