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CVE-2026-76420

Cisco Secure Firewall Management Center Software Impersonated sftunnel Connection Vulnerability

Published: Sep 16, 2026Updated: Sep 17, 2026 Sources: CVE List NVDCWE-285
9.0CRITICAL
NVD MITRE
EPSS Score
0.4%
Top 69.5%
CISA KEV
Not in KEV
Exploits
0 Known
Remediation
No Fix Available
Self-Check
Not available

Description

A vulnerability in the internal configuration of the Apache JServ Protocol (AJP) connector for Cisco Secure FMC Software could allow an unauthenticated, remote attacker to impersonate a peer device. This vulnerability is due to incorrect initialization of encryption parameters for the AJP connector at boot time. An attacker could exploit this vulnerability by sending crafted packets to the AJP connector. A successful exploit could allow the attacker to execute commands as root and gain full control over the FMC REST APIs on the affected device. Note: This vulnerability can be exploited only if the valid sftunnel connection between Cisco Secure FMC Software and Cisco Secure FTD Software is down.

In plain language

AI Act now

Businesses running Cisco Secure Firewall Management Center should treat this as an immediate concern: a public attack is available and no fix information has been published.

Executive summary

Unauthenticated remote root command execution is possible through crafted Apache JServ Protocol connector traffic because encryption parameters are initialized incorrectly at boot, allowing peer-device impersonation when the sftunnel connection is down.

If affected, business impact
Full management system takeoverFirewall policy tamperingNetwork access disruptionSensitive configuration exposureService outage risk

What to do now

  1. Confirm whether you run Cisco Secure Firewall Management Center and whether any sftunnel connection to Cisco Secure Firewall Threat Defense is down.
  2. Ask Cisco or your support provider for the published fixed version; no fixed version is available in the current advisories.
  3. Until Cisco provides a fix, restore and maintain sftunnel connections, restrict access to the management appliance, and investigate unexpected management API activity.
May need vendor / contractor work

CVSS Vector Breakdown

AV:NAC:HPR:NUI:NS:CC:HI:HA:H
Exploitability
AV:NAttack Vector
Network
AC:HAttack Complexity
High
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:CScope
Changed
Impact
C:HConfidentiality
High
I:HIntegrity
High
A:HAvailability
High
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Weaknesses

CWE-285

Affected Products

Cisco
commercial·USaka cisco systems inc., cisco systems
Cisco Secure Firewall Management Center (FMC)
Networking Infrastructure

Exploitability

0 exploit sources identified

Exploit details including PoC links, Metasploit modules, and scanner templates are available after registration.

View exploit details
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References

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-fmc2-multivulns-HXgcqRG
sec.cloudapps.cisco.com
News mentions
1

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