CVE-2026-20323
published 2026-09-16CVE-2026-20323: A vulnerability in the sftunnel inter-device communication protocol of Cisco Secure FMC Software and Cisco Secure FTD Software could allow an unauthenticated…
PriorityP349high8.3CVSS 3.1
AVAACHPRNUINSCCHIHAH
EPSS
0.09%
0.4th percentile
A vulnerability in the sftunnel inter-device communication protocol of Cisco Secure FMC Software and Cisco Secure FTD Software could allow an unauthenticated, adjacent attacker to impersonate the peer device and obtain access at the level of the manager role, which is equivalent to root.
This vulnerability is due to improper management of the TLS certificate for the sftunnel management connection. An attacker could exploit this vulnerability by connecting to the sftunnel port using a crafted TLS certificate. A successful exploit could allow the attacker to become a registered sftunnel peer with root access.
Note: The attack is successful only if the sftunnel connection is down or the attack can disrupt the sftunnel connection long enough to execute the attack.
Affected
130 ranges· showing 25
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| cisco | cisco_secure_firewall_management_center | — | — |
| cisco | cisco_secure_firewall_management_center | — | — |
| cisco | cisco_secure_firewall_management_center | — | — |
| cisco | cisco_secure_firewall_management_center | — | — |
| cisco | cisco_secure_firewall_management_center | — | — |
| cisco | cisco_secure_firewall_management_center | — | — |
| cisco | cisco_secure_firewall_management_center | — | — |
| cisco | cisco_secure_firewall_management_center | — | — |
| cisco | cisco_secure_firewall_management_center | — | — |
| cisco | cisco_secure_firewall_management_center | — | — |
| cisco | cisco_secure_firewall_management_center | — | — |
| cisco | cisco_secure_firewall_management_center | — | — |
| cisco | cisco_secure_firewall_management_center | — | — |
| cisco | cisco_secure_firewall_management_center | — | — |
| cisco | cisco_secure_firewall_management_center | — | — |
| cisco | cisco_secure_firewall_management_center | — | — |
| cisco | cisco_secure_firewall_management_center | — | — |
| cisco | cisco_secure_firewall_management_center | — | — |
| cisco | cisco_secure_firewall_management_center | — | — |
| cisco | cisco_secure_firewall_management_center | — | — |
| cisco | cisco_secure_firewall_management_center | — | — |
| cisco | cisco_secure_firewall_management_center | — | — |
| cisco | cisco_secure_firewall_management_center | — | — |
| cisco | cisco_secure_firewall_management_center | — | — |
| cisco | cisco_secure_firewall_management_center | — | — |
Stop checking back — get the weekly exploitation signal.
Every Monday: what got weaponized or added to CISA KEV in the last seven days — each CVE cross-linked to its PoC, Nuclei template, and detection rule. Free, one email a week, unsubscribe in one click.
VulDB
Cisco Secure Firewall Management Center sftunnel certificate validation
vuldb·2026-09-16·CVSS 8.3
CVE-2026-20323 [HIGH] Cisco Secure Firewall Management Center sftunnel certificate validation
A vulnerability identified as problematic has been detected in Cisco Secure Firewall Management Center and Secure Firewall Threat Defense Software. Affected by this vulnerability is an unknown functionality of the component sftunnel. This manipulation causes improper certificate validation.
The identification of this vulnerability is CVE-2026-20323. It is possible to initiate the attack remotely. There is no exploit available.
You should upgrade the affected component.
GHSA
A vulnerability in the sftunnel inter-device communication protocol of Cisco Secure FMC Software and Cisco Secure FTD Software could allow an unauthenticated, adjacent attacker to impersonate the peer
ghsa_unreviewed·2026-09-16
CVE-2026-20323 [HIGH] CWE-295 A vulnerability in the sftunnel inter-device communication protocol of Cisco Secure FMC Software and Cisco Secure FTD Software could allow an unauthenticated, adjacent attacker to impersonate the peer
A vulnerability in the sftunnel inter-device communication protocol of Cisco Secure FMC Software and Cisco Secure FTD Software could allow an unauthenticated, adjacent attacker to impersonate the peer device and obtain access at the level of the manager role, which is equivalent to root.
This vulnerability is due to improper management of the TLS certificate for the sftunnel management connection. An attacker could exploit this vulnerability by connecting to the sftunnel port using a crafted TLS certificate. A successful exploit could allow the attacker to become a registered sftunnel peer with root access.
Note: The attack is successful only if the sftunnel connection is down or the attack can disrupt the sftunnel connection long enough to execute the attack.
No detection rules found.
No public exploits indexed.
No writeups or analysis indexed.
2026-09-16
Published