CVE-2026-76676 in EdgeConnect SD-WAN
Summary
by MITRE • 09/15/2026
Buffer overflow vulnerabilities exist in the underlying operating system of EdgeConnect SD-WAN Gateways that could allow an unauthenticated adjacent attacker to execute arbitrary code if certain preconditions outside of the attacker's control are met. Successful exploitation could allow an attacker to execute arbitrary code as a privileged user on the underlying operating system leading to complete system compromise.
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Analysis
by VulDB Data Team • 09/15/2026
The identified vulnerability represents a critical security flaw within the EdgeConnect SD-WAN Gateway infrastructure, specifically rooted in buffer overflow conditions present in the underlying operating system components. This type of memory corruption error typically arises when an application writes more data to a fixed-length block of memory than it is allocated to hold, causing adjacent memory locations to be overwritten with unintended values. In this specific context, the vulnerability affects the core OS layers rather than just the high-level SD-WAN management applications, which significantly elevates the severity and potential impact of the exploit. The presence of such a flaw indicates that input validation or bounds checking mechanisms within these system components are insufficient to handle malformed or excessively large data inputs effectively.
From an attack vector perspective, this vulnerability is particularly dangerous because it can be exploited by an unauthenticated attacker who has adjacent network access. Adjacent attackers typically reside on the same physical network segment or virtual LAN as the target device, such as through a compromised host on the local subnet or via direct wired connection to the gateway's management interface. The requirement for certain preconditions outside of the attacker's control suggests that while initial access is relatively straightforward given adjacency, successful exploitation may depend on specific timing conditions, configuration states, or trigger mechanisms within the OS services. Despite these dependencies, the ability to execute arbitrary code as a privileged user upon success renders the risk profile extremely high.
The operational impact of successfully exploiting this buffer overflow extends far beyond simple data exfiltration. Since the attacker can achieve execution with elevated privileges on the underlying operating system, they effectively gain full control over the EdgeConnect SD-WAN Gateway. This level of compromise allows for complete system takeover, enabling the adversary to install backdoors, modify routing tables, intercept and manipulate traffic flowing through the SD-WAN fabric, or pivot further into other parts of the enterprise network. Given that SD-WAN gateways often serve as critical chokepoints for organizational connectivity, compromising one such device can lead to widespread disruption of business operations and potential exposure of sensitive data traversing the wide area network.
This vulnerability aligns with Common Weakness Enumeration (CWE) category CWE-120, which describes Buffer Copy without Checking Size of Input, a classic memory safety issue prevalent in systems programming languages like C or C++. Furthermore, from an adversary tactics perspective as defined by MITRE ATT&CK, this flaw facilitates the Initial Access and Execution techniques, specifically allowing for remote code execution via network services. The ability to escalate privileges post-exploitation maps directly to privilege escalation vectors where attackers leverage OS-level flaws to gain administrative control.
To mitigate this risk, immediate action is required to apply vendor-provided patches or firmware updates that address the underlying buffer overflow in the operating system components of the EdgeConnect SD-WAN Gateways. Organizations should verify their inventory for affected versions and prioritize patching based on exposure levels. Additionally, network segmentation strategies should be reviewed to ensure that management interfaces are not unnecessarily exposed to adjacent untrusted networks. Implementing strict access control lists (ACLs) restricting traffic to these gateways only from known, trusted IP ranges can reduce the attack surface available to potential adversaries. Continuous monitoring for anomalous behavior on SD-WAN devices is also recommended to detect any attempted exploitation activities in real-time.