CVE-2026-20316 in Secure Firewall Management Center
Summary
by MITRE • 07/29/2026
A vulnerability in the web interface of Cisco Secure Firewall Management Center (FMC) Software could allow an unauthenticated, remote attacker to log in to an affected device using a low-privileged account to access sensitive data within the impacted systems.
This vulnerability is due to the presence of static user credentials for a low-privileged account. An attacker could exploit this vulnerability by using the account to log in to an affected system. A successful exploit could allow the attacker to log in to the affected system and access sensitive data as the low-privileged user. Note: If the FMC management interface does not have public internet access, the attack surface that is associated with this vulnerability is reduced. Cisco has assigned this security advisory a Security Impact Rating (SIR) of High rather than Medium as the score indicates. The reason is that this vulnerability can be used with other Cisco Secure FMC Software vulnerabilities to elevate privileges.
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Analysis
by VulDB Data Team • 07/29/2026
This vulnerability exists within the web interface of Cisco Secure Firewall Management Center software, representing a critical authentication flaw that enables unauthenticated remote attackers to gain access to affected systems using static credentials for a low-privileged account. The presence of hardcoded or static user credentials violates fundamental security principles and creates a persistent backdoor that remains exploitable regardless of system updates or password changes. This vulnerability falls under the CWE-798 category of using hardcoded credentials, which is classified as a severe weakness in software design that directly enables unauthorized access to systems and data.
The technical exploitation of this vulnerability requires minimal effort from an attacker, as they need only to identify and utilize the static credentials to establish a valid session within the FMC management interface. Once authenticated, the attacker operates with the privileges of a low-privileged user account, which while limited in scope, still provides access to sensitive configuration data, logs, and potentially other system information that could be leveraged for further attacks. This weakness represents a classic privilege escalation vector where the initial low-privileged access serves as a foothold for more comprehensive compromise.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it creates an attack surface that can be combined with other vulnerabilities present in the Cisco Secure FMC Software to achieve privilege elevation. This chaining capability significantly increases the potential damage and makes the vulnerability particularly dangerous in environments where additional weaknesses may exist. The security impact rating of High assigned by Cisco reflects not only the immediate access risk but also the potential for this vulnerability to serve as a stepping stone for more sophisticated attacks, aligning with ATT&CK technique T1078 for Valid Accounts and T1566 for Phishing. Organizations utilizing FMC software face significant risks including data exposure, configuration manipulation, and potential lateral movement within their network infrastructure.
Mitigation strategies should prioritize immediate credential rotation and the implementation of strong access controls within the FMC environment. Network segmentation can reduce the attack surface by limiting direct internet access to the management interface, while implementing multi-factor authentication for any remaining administrative access provides additional protection layers. System administrators should conduct comprehensive audits of all user accounts and credentials, removing or disabling static accounts that are no longer required for system operation. The vulnerability also highlights the importance of regular security assessments and adherence to secure coding practices that prevent the inclusion of hardcoded credentials in production software. Organizations should also consider implementing network monitoring solutions to detect unauthorized access attempts and establish incident response procedures specifically designed to address credential-based attacks, as this vulnerability represents a clear violation of the principle of least privilege and proper access control implementation.