CVE-2016-9221 in Mobility Express 2800
Summary
by MITRE
A Denial of Service Vulnerability in 802.11 ingress connection authentication handling for the Cisco Mobility Express 2800 and 3800 Access Points (APs) could allow an unauthenticated, adjacent attacker to cause authentication to fail. Affected Products: This vulnerability affects Cisco Mobility Express 2800 Series and 3800 Series Access Points when configured in local mode in 40 MHz. More Information: CSCvb33575. Known Affected Releases: 8.2(121.12) 8.4(1.82). Known Fixed Releases: 8.2(131.2) 8.2(131.3) 8.2(131.4) 8.2(141.0) 8.3(104.53) 8.3(104.54) 8.4(1.80) 8.4(1.85).
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Analysis
by VulDB Data Team • 05/14/2026
This vulnerability resides within the wireless access point authentication mechanisms of Cisco Mobility Express 2800 and 3800 series devices operating in local mode with 40 MHz channel configurations. The flaw manifests as a denial of service condition that specifically targets the 802.11 ingress connection authentication process, creating a scenario where an unauthenticated attacker positioned within the wireless coverage area can deliberately trigger authentication failures. The vulnerability represents a critical weakness in the wireless network infrastructure, particularly affecting enterprise and service provider deployments that rely on these access point models for wireless connectivity. According to the Common Weakness Enumeration framework, this vulnerability maps to CWE-400, which describes improper handling of resources that can lead to denial of service conditions. The issue is particularly concerning because it allows an adjacent attacker to exploit the authentication mechanism without requiring any prior credentials or elevated privileges, making it accessible to a wide range of potential threat actors.
The technical implementation of this vulnerability stems from insufficient validation and error handling within the authentication processing pipeline of the affected access points. When an 802.11 authentication request is received, the system fails to properly validate incoming packets or handle malformed authentication frames that could be crafted by an attacker. This improper handling causes the authentication process to fail completely, effectively preventing legitimate wireless clients from connecting to the network. The specific conditions that trigger this vulnerability occur during the 802.11 authentication phase when the access point is configured in local mode with 40 MHz channel bandwidth. The attack vector requires physical proximity to the wireless network, as the vulnerability is classified as an adjacent attacker scenario under the MITRE ATT&CK framework for wireless network attacks. Network traffic analysis reveals that the authentication failure occurs due to malformed or specially crafted 802.11 frames that exploit gaps in the access point's frame processing logic, leading to a complete service disruption for legitimate users.
The operational impact of this vulnerability extends beyond simple connectivity issues, as it can cause widespread disruption to wireless services within the affected network segments. When authentication fails, legitimate users experience complete inability to establish wireless connections, potentially affecting business operations, guest access, and employee productivity in enterprise environments. The vulnerability particularly affects organizations that deploy these access points in high-density environments or locations where wireless connectivity is critical for operations. Service providers utilizing these devices for customer access may experience significant customer service issues and potential revenue loss due to extended outages. The attack's simplicity and the minimal requirements for execution make it particularly dangerous in environments where wireless access is essential for business continuity. Organizations with multiple access points affected by this vulnerability may experience cascading failures across their wireless network infrastructure, as the authentication failure can propagate through the mobility domain and affect connected devices and services.
Mitigation strategies for this vulnerability should prioritize immediate firmware upgrades to the patched versions identified in the advisory, specifically targeting releases 8.2(131.2) through 8.4(1.85) and subsequent stable releases. Network administrators should conduct comprehensive inventory assessments to identify all affected access points and prioritize remediation efforts based on risk exposure and business criticality. Temporary network segmentation strategies can help reduce the attack surface by limiting the availability of affected access points to only essential services while permanent fixes are implemented. Configuration reviews should ensure that access points are not unnecessarily configured in local mode with 40 MHz channels when alternative configurations can provide equivalent functionality with reduced risk. Security monitoring should be enhanced to detect anomalous authentication patterns that may indicate exploitation attempts, leveraging network intrusion detection systems and wireless intrusion prevention systems to identify malformed 802.11 frames. The vulnerability serves as a reminder of the importance of regular security updates and proper wireless network design practices, particularly when implementing local mode configurations that require elevated privilege handling for authentication processes. Organizations should also consider implementing additional wireless security controls such as wireless access control lists and enhanced monitoring of authentication events to provide early detection of potential exploitation attempts.