Cisco Security Advisories guidance
Vendor revision: Sep 16, 2026To remediate these vulnerabilities, Cisco strongly recommends that customers upgrade to the fixed software that is indicated in the advisories.
Vulnerability intelligence
CVE-2026-20295 and is rated High severity with a CVSS score of 8.6. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.
To remediate these vulnerabilities, Cisco strongly recommends that customers upgrade to the fixed software that is indicated in the advisories.
Cisco has released software updates that address these vulnerabilities.
A vulnerability in the sftunnel inter-device communication protocol of Cisco Secure FMC Software and Cisco Secure FTD Software could allow an unauthenticated, remote attacker to exhaust the available memory of an affected device.
This vulnerability is due to improper management of memory resources during sftunnel TLS connection setup. An attacker could exploit this vulnerability by sending crafted sftunnel TLS frames to an affected device during the connection setup.
A successful exploit could allow the attacker to exhaust the available memory on the affected device, which could result in a DoS condition.
Source: NVD