CVE-2025-20202 in IOS XE
Summary
by MITRE • 05/07/2025
A vulnerability in Cisco IOS XE Wireless Controller Software could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition on an affected device.
This vulnerability is due to insufficient input validation of access point (AP) Cisco Discovery Protocol (CDP) neighbor reports when they are processed by the wireless controller. An attacker could exploit this vulnerability by sending a crafted CDP packet to an AP. A successful exploit could allow the attacker to cause an unexpected reload of the wireless controller that is managing the AP, resulting in a DoS condition that affects the wireless network.
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Analysis
by VulDB Data Team • 05/07/2025
This vulnerability exists within Cisco IOS XE Wireless Controller Software and represents a significant security weakness that could compromise wireless network availability. The flaw stems from inadequate validation mechanisms within the wireless controller's processing of Cisco Discovery Protocol (CDP) neighbor reports from access points. When an access point receives a specially crafted CDP packet, the wireless controller fails to properly validate the incoming data, creating an exploitable condition that can be leveraged by adjacent attackers. The vulnerability specifically targets the controller's handling of neighbor information, which is a fundamental component of wireless network management and device discovery processes. This type of flaw demonstrates a critical oversight in input sanitization and validation protocols that are essential for maintaining system stability and security in network infrastructure devices.
The technical exploitation of this vulnerability occurs through the manipulation of CDP packets that are normally used for network discovery and device identification purposes. An attacker positioned in the same network segment as an affected access point can craft malicious CDP packets containing malformed or unexpected data structures that bypass the controller's input validation checks. When the wireless controller processes these malformed CDP neighbor reports, the insufficient validation leads to a condition where the controller's internal state becomes corrupted or unstable. This corruption ultimately triggers an unexpected system restart or reload operation, effectively causing the wireless controller to reboot and temporarily removing it from service. The vulnerability operates at the network protocol level, leveraging the legitimate CDP functionality while exploiting the controller's failure to properly validate incoming neighbor information.
The operational impact of this vulnerability extends beyond simple network disruption to potentially affect business continuity and wireless network reliability. When a wireless controller experiences an unexpected reload due to this vulnerability, it can cause complete loss of wireless connectivity for all associated access points and connected clients. The DoS condition affects the entire wireless network infrastructure managed by the compromised controller, potentially impacting thousands of users depending on the network size. Organizations may experience significant downtime during the recovery period while the controller restarts and re-establishes network connections. The adjacent attacker requirement means that physical or network proximity is necessary for exploitation, but this limitation does not reduce the severity of impact since wireless controllers are often deployed in accessible locations within network facilities. This vulnerability represents a critical threat to wireless infrastructure availability and could be particularly damaging in enterprise or mission-critical environments where wireless connectivity is essential.
Mitigation strategies for this vulnerability should focus on both immediate protective measures and long-term architectural improvements. Network administrators should implement network segmentation and access controls to limit the ability of unauthorized users to send malicious CDP packets to access points. The implementation of CDP filtering or disabling CDP on access points where it is not required can significantly reduce the attack surface. Cisco has released software updates and patches that address this vulnerability by strengthening input validation mechanisms for CDP neighbor reports. Organizations should prioritize applying these security updates as soon as possible and conduct thorough testing to ensure compatibility with existing network configurations. Network monitoring should be enhanced to detect unusual patterns in CDP traffic that might indicate exploitation attempts. The vulnerability aligns with CWE-20, which addresses "Improper Input Validation," and represents a classic example of how insufficient validation of externally-provided data can lead to system instability and denial of service conditions. From an ATT&CK framework perspective, this vulnerability maps to techniques involving privilege escalation and denial of service through network protocol manipulation, making it a significant concern for security operations centers monitoring wireless infrastructure.