CVE-2026-20323 Cisco Secure FMC & FTD Software - Privilege Escalation

Cisco Secure FMC Software and Cisco Secure FTD Software contain a privilege escalation caused by improper TLS certificate management in the sftunnel inter-device communication protocol, letting unauthenticated adjacent attackers impersonate peer devices and gain manager-level (root) access, exploit requires sftunnel connection to be down or disrupted.

CVSS base score 8.3 /10
High
CISA KEV
Not listed
Public exploit
None known
EPSS
0.09% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Privilege Escalation
Impact
Privilege Escalation
CVSS vector
CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
Published
16 September 2026
Updated
15 October 2026
Weakness
CWE-295

Vendor fix

Update to the latest available version that addresses TLS certificate management in sftunnel.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

References

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