Vulnerability in Cisco Secure Firewall Management Center (Fmc)

CVE-2026-20295

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.

CVSS v3 metric

CVSS v3 base score 8.6 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-20295?
CVE-2026-20295 is a high-severity vulnerability in Cisco Secure Firewall Management Center (Fmc), classified under CWE-789. CVSS score: 8.6/10. Published 2026-09-16.
How severe is CVE-2026-20295?
High severity. CVSS v3 base score is 8.6 out of 10.