CVE-2026-20341

A vulnerability in the sftunnel inter-device communication protocol of Cisco Secure FMC Software could allow an authenticated, remote attacker to obtain root privileges. This vulnerability is due to unsecured deserialization of untrusted data over the sftunnel management connection. An attacker could exploit this vulnerability by sending crafted sftunnel remote procedure calls (RPCs). A successful exploit could allow the attacker to gain root privileges on a device that is running Cisco Secure FMC Software and its high-availability peer. To exploit this vulnerability, the attacker must have valid administrative credentials on a managed Cisco FTD device.

CVSS v3 9.1 CRITICAL

9.1^/10

CVSS v3 : CRITICAL

Vector :

Exploitability : 2.3 / Impact : 6.0

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required HIGH

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope CHANGED

References

Link	Resource
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-fmc-mulivulns-4PsnFwvx

Configurations

No configuration.

History

16 Sep 2026, 20:17

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-09-16 20:17

Updated : 2026-09-17 17:16

NVD link : CVE-2026-20341

Mitre link : CVE-2026-20341

CVE.ORG link : CVE-2026-20341

JSON object : View

Products Affected

No product.

CWE

CWE-502

Deserialization of Untrusted Data

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An attacker could exploit this vulnerability by sending crafted sftunnel remote procedure calls (RPCs). A successful exploit could allow the attacker to gain root privileges on a device that is running Cisco Secure FMC Software and its high-availability peer.\r\nTo exploit this vulnerability, the attacker must have valid administrative credentials on a managed Cisco FTD device."}], "lastModified": "2026-09-17T17:16:39.660", "sourceIdentifier": "psirt@cisco.com"}