CVE-2026-76455 in NX-OS Software
Summary
by MITRE • 10/07/2026
As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco NX-OS engineering team has conducted a comprehensive internal security review. This review resulted in a software hardening release that addresses multiple internally discovered vulnerabilities.
The vulnerabilities tracked by CVE-2026-76455 are related to improper access control issues that are grouped under the Common Weakness Enumeration (CWE) CWE-284.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 10/07/2026
Cisco NX-OS, a critical network operating system powering many of the world's largest data centers and enterprise networks, has been updated to address significant security deficiencies identified through rigorous internal engineering reviews. The specific vulnerability tracked under CVE-2026-76455 represents a fundamental failure in access control mechanisms within the software architecture. This flaw is categorized under Common Weakness Enumeration identifier CWE-284, which denotes Improper Access Control. In practical terms, this means that the system failed to enforce appropriate restrictions on authenticated users or processes, allowing actions or data access that should have been restricted based on user roles and permissions. Such vulnerabilities are particularly dangerous in network infrastructure because they can undermine the integrity of the entire management plane, potentially leading to unauthorized configuration changes, service disruption, or further exploitation through privilege escalation.
The technical nature of CWE-284 flaws often involves insufficient checks during authorization decisions. In the context of Cisco NX-OS, this could manifest as a scenario where an authenticated user with limited privileges is able to execute commands or access sensitive system resources reserved for administrators. This misalignment between intended security policy and actual enforcement creates a gap that attackers can exploit without needing to discover additional zero-day exploits in other components. The presence of such vulnerabilities highlights the complexity inherent in maintaining robust security boundaries within highly complex, feature-rich operating systems designed for high-performance networking environments.
From an operational perspective, the impact of this vulnerability is severe due to its potential to compromise network stability and confidentiality. An attacker who successfully leverages improper access control could gain unauthorized administrative privileges, effectively taking full control of the affected device. This level of access allows for the modification of routing tables, interception of traffic, or deployment of malicious configurations that can disrupt service availability across interconnected networks. Furthermore, because NX-OS devices often serve as critical infrastructure nodes, compromising one such system can provide a foothold for lateral movement within an enterprise network, aligning with tactics described in the MITRE ATT&CK framework related to privilege escalation and unauthorized access.
To mitigate these risks, organizations running affected versions of Cisco NX-OS must apply the recommended software hardening release immediately upon availability. It is crucial to verify that all instances of the vulnerable code paths are updated across the network infrastructure. Additionally, implementing defense-in-depth strategies such as strict role-based access control policies, regular auditing of administrative actions, and monitoring for anomalous behavior can help detect attempts to exploit these weaknesses before they result in a full compromise. Continuous vigilance and adherence to Cisco's security advisories remain essential components of maintaining a resilient network environment against evolving threats targeting infrastructure operating systems.