CVE-2026-76457 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-2026-76457 are related to out-of-bounds read issues that are grouped under the Common Weakness Enumeration (CWE) CWE-125.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 10/07/2026
Cisco has released a software hardening update for NX-OS following an internal security review aimed at addressing multiple internally discovered vulnerabilities, including CVE-2026-76457 which is classified under the Common Weakness Enumeration identifier CWE-125 representing out-of-bounds read issues. This proactive measure underscores Cisco's commitment to maintaining product quality and securing network infrastructure against potential exploitation vectors that could compromise system integrity or availability.
The specific technical flaw associated with CVE-2026-76457 involves an out-of-bounds memory read, a condition where software attempts to access data beyond the boundaries of allocated memory buffers. This type of vulnerability typically arises from insufficient validation of input parameters or improper handling of array indices during processing operations within the NX-OS codebase. When such a boundary check fails, the application may retrieve unintended information from adjacent memory locations that were not intended for public consumption.
From an operational perspective, out-of-bounds read vulnerabilities can lead to several adverse outcomes depending on the context in which they are exploited. The most immediate risk is the potential disclosure of sensitive internal data structures or cryptographic keys stored in neighboring memory regions. In some scenarios, if the accessed memory contains executable code pointers or control flow metadata, an attacker might leverage this information leak to facilitate more complex attacks such as remote code execution through subsequent exploitation steps like heap spraying or return-oriented programming techniques. Although out-of-bounds reads are generally considered less severe than write variants because they do not directly allow arbitrary code injection, the intelligence gained can significantly lower the barrier for further compromise.
In terms of threat modeling and industry standards mapping, this vulnerability aligns with ATT&CK technique T1083 which covers file and directory discovery as well as broader information gathering phases where attackers seek to understand the target environment before launching deeper attacks. The lack of proper bounds checking reflects a fundamental design weakness often categorized under CWE-20 for improper input validation leading to memory safety violations. Network administrators should recognize that while this specific CVE does not immediately imply full system takeover, it represents a critical step in an attack chain where initial information leakage enables subsequent privilege escalation or persistent access strategies.
To mitigate the risks associated with CVE-2026-76457 and similar out-of-bounds read conditions, organizations running Cisco NX-OS should prioritize applying the provided software hardening release as soon as feasible within their maintenance windows. Beyond patching, implementing network segmentation to limit lateral movement in case of partial compromise is advisable. Additionally, enabling comprehensive logging and monitoring for anomalous memory access patterns or unexpected data exfiltration attempts can help detect exploitation activities early. Regular security assessments and code reviews focusing on input validation mechanisms are essential preventive measures against future occurrences of CWE-125 type vulnerabilities across network operating systems.