CVE-2026-76677 in EdgeConnect SD-WAN Gateways
Summary
by MITRE • 09/15/2026
A privilege escalation vulnerability exists in the API of EdgeConnect SD-WAN Gateways. Successful exploitation could allow a remote low-privileged authenticated user to achieve administrative privilege on the web-management interface leading to complete system compromise.
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Analysis
by VulDB Data Team • 09/15/2026
The identified security flaw resides within the application programming interface of Cisco's EdgeConnect Software Defined Wide Area Network gateways, representing a critical failure in access control mechanisms that governs how users interact with the device's management plane. This vulnerability specifically targets the authentication and authorization logic embedded within the web-management interface API endpoints. The core technical deficiency involves an improper enforcement of role-based access controls, where the system fails to adequately validate whether a user possessing low-privileged credentials is attempting to execute actions or invoke functions that are strictly reserved for administrative roles. By manipulating specific HTTP requests sent to these API endpoints, an attacker can bypass standard permission checks and escalate their session privileges from a restricted operational level to full administrative control without requiring valid high-level credentials or exploiting separate authentication flaws.
From a technical perspective, this flaw aligns with CWE-269, which classifies Improper Privilege Control vulnerabilities where the software does not properly restrict the actions of authorized users in terms of privilege levels. The exploitation vector is remote and requires only authenticated access at a low level, meaning that any user account with basic login capabilities can potentially leverage this defect. Once an attacker successfully exploits this condition by sending crafted requests to the API, they gain the ability to modify system configurations, manage network policies, install malicious software, or exfiltrate sensitive data stored on the gateway. This effectively results in a complete compromise of the EdgeConnect SD-WAN infrastructure, as administrative access allows for total control over the device's operational state and its role within the broader enterprise network topology.
The operational impact of this vulnerability is severe due to the central role that EdgeConnect gateways play in modern hybrid networking environments. These devices serve as critical choke points for traffic between branch offices, data centers, and cloud services. Compromising an administrative account on such a device allows threat actors to intercept, modify, or drop network traffic across multiple sites simultaneously. Furthermore, it enables the attacker to disable security features such as intrusion prevention systems or firewall rules, thereby creating persistent backdoors within the corporate perimeter. This level of access facilitates lateral movement into internal networks and can lead to significant data breaches, operational disruption, and compliance violations depending on the sensitivity of the information traversing the compromised infrastructure.
In terms of threat modeling, this vulnerability is categorized under MITRE ATT&CK technique T1078, specifically Valid Accounts, as it relies on existing low-privileged credentials being used to gain higher-level access through logical flaws rather than credential theft or brute force attacks. It also relates to T1548, Abuse Elevation Control Mechanism, where the attacker abuses system mechanisms designed to control privilege levels. The attack path is straightforward for any authenticated user with network connectivity to the management interface, making it a high-risk issue that requires immediate attention from security operations teams responsible for SD-WAN infrastructure maintenance and monitoring.
To mitigate this risk, organizations must apply the vendor-provided software updates or patches that address the API authorization logic as soon as they become available. Until patching is implemented, administrators should enforce strict network segmentation to ensure that only authorized management stations can access the web-management interface of EdgeConnect gateways. Implementing multi-factor authentication for all administrative accounts adds an additional layer of security, although it does not directly prevent exploitation by low-privileged users who already have valid credentials. Additionally, deploying Web Application Firewalls with rulesets designed to detect and block anomalous API calls or privilege escalation attempts can provide a temporary compensating control. Continuous monitoring of access logs for unusual patterns in role changes or administrative actions is also recommended to detect potential exploitation activities early in the attack lifecycle.