CVE-2016-2783 in Fabric Connect Virtual Services Platform
Summary
by MITRE
Avaya Fabric Connect Virtual Services Platform (VSP) Operating System Software (VOSS) before 4.2.3.0 and 5.x before 5.0.1.0 does not properly handle VLAN and I-SIS indexes, which allows remote attackers to obtain unauthorized access via crafted Ethernet frames.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 05/14/2026
The vulnerability identified as CVE-2016-2783 affects Avaya Fabric Connect Virtual Services Platform operating system software versions prior to 4.2.3.0 and 5.x versions before 5.0.1.0. This security flaw resides within the VOSS software that governs the network infrastructure capabilities of the VSP platform. The vulnerability stems from improper handling of VLAN and I-SIS indexes, which are critical components for network segmentation and identity management within the fabric environment. The issue manifests when the system processes crafted Ethernet frames that exploit these index handling mechanisms, potentially allowing malicious actors to bypass normal access controls and gain unauthorized entry into the network infrastructure.
This technical flaw represents a significant security weakness that operates at the network protocol level, specifically targeting the way the software manages virtual local area network identifiers and identity services infrastructure indexes. The improper index handling creates a pathway for remote attackers to manipulate network traffic in ways that could compromise the integrity of the fabric connectivity. The vulnerability is classified under CWE-20 as "Improper Input Validation" and falls within the ATT&CK technique T1071.001 for application layer protocol usage. The software's failure to properly validate and sanitize the VLAN and I-SIS index values in incoming Ethernet frames creates an attack surface that can be exploited without requiring physical access or elevated privileges.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it potentially allows attackers to disrupt network services, escalate privileges, and gain deeper access to the fabric infrastructure. Network administrators may experience unauthorized data access, potential service disruption, and compromised network segmentation that could affect multiple connected systems. The vulnerability affects organizations that rely on Avaya's fabric connectivity solutions for their network infrastructure, particularly those implementing virtual services platforms where network isolation is critical for security posture. Attackers could leverage this weakness to establish persistent access points within the network fabric, potentially leading to broader compromise of connected systems and data exfiltration opportunities.
Organizations should prioritize immediate patching of affected systems to address this vulnerability, ensuring that all instances of VOSS software are updated to versions 4.2.3.0 or later for the 4.2.x release line and 5.0.1.0 or later for the 5.x release line. Network monitoring should be enhanced to detect anomalous Ethernet frame patterns that might indicate exploitation attempts, while access controls should be reviewed to ensure that the compromised index handling does not allow privilege escalation. Security teams should implement network segmentation controls and consider deploying intrusion detection systems that can identify and alert on suspicious VLAN or I-SIS index manipulation patterns. Additionally, regular security assessments should verify that the updated software maintains proper index validation mechanisms and that no residual vulnerabilities remain in the network infrastructure components. The vulnerability demonstrates the critical importance of proper input validation in network infrastructure software and highlights the need for continuous security testing of core network protocols to prevent similar weaknesses from being exploited in enterprise environments.