CVE-2026-76420
Cisco Secure Firewall Management Center Software Impersonated sftunnel Connection Vulnerability
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.
INFO
Published Date :
Sept. 16, 2026, 5:18 p.m.
Last Modified :
Sept. 17, 2026, 12:18 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-76420
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | CRITICAL | [email protected] |
Solution
- Update Cisco Secure FMC Software to the latest version.
- Disable AJP connectors if not actively used.
- Ensure sftunnel connections are stable.
- Monitor for unauthorized access attempts.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-76420.
| URL | Resource |
|---|---|
| https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-fmc2-multivulns-HXgcqRG |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-76420 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-76420
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-76420 vulnerability anywhere in the article.
-
The Hacker News
Cisco Warns of New Zero-Day ISE Auth Bypass (CVSS 10.0) Exploited in Active Attacks
Cisco has warned of a fresh maximum-severity security flaw impacting Identity Services Engine (ISE) that has come under active exploitation. The vulnerability, tracked as CVE-2026-76460 (CVSS score: 1 ... Read more
The following table lists the changes that have been made to the
CVE-2026-76420 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Sep. 17, 2026
Action Type Old Value New Value Changed SSVC {'id': 'CVE-2026-76420', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-09-16T00:00:00+00:00'} {'id': 'CVE-2026-76420', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-09-17T03:57:15.366414Z'} -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Sep. 17, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-76420', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-09-16T00:00:00+00:00'} -
New CVE Received by [email protected]
Sep. 16, 2026
Action Type Old Value New Value Added 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. Added CVSS V3.1 AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H Added CWE CWE-285 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/76xxx/CVE-2026-76420.json">CVE-2026-76420</a> Added Reference https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-fmc2-multivulns-HXgcqRG