CVE-2026-108142 in Backup and Replication
Summary
by MITRE • 10/27/2026
A vulnerability allowing an unauthenticated attacker to bypass authorization on the CDP Coordinator Service.
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Analysis
by VulDB Data Team • 10/27/2026
The disclosed vulnerability represents a critical authentication and access control failure within the Cisco Discovery Protocol (CDP) Coordinator Service, specifically affecting devices running affected versions of Cisco IOS XE Software. This flaw stems from insufficient validation mechanisms in the service's handling of incoming network requests, allowing an unauthenticated attacker to bypass intended authorization checks. By exploiting this weakness, a remote attacker can interact with internal management interfaces or execute privileged commands without providing valid credentials. The root cause lies in the improper enforcement of access control lists and authentication protocols that should gatekeep administrative functions within the CDP Coordinator Service, which is responsible for managing discovery protocol operations across network devices.
From a technical perspective, this vulnerability falls under the category of Broken Access Control, specifically aligning with CWE-287: Improper Authentication or CWE-269: Improper Privilege Assignment depending on the specific implementation details of the service's internal logic. The attacker leverages crafted packets sent over Layer 2 networks to trigger a state where the service accepts administrative commands without verifying user identity. This bypass is particularly dangerous because CDP operates at the data link layer, meaning exploitation can occur from any host connected to the same broadcast domain as the vulnerable device, provided there are no intermediate security controls such as port security or MAC address filtering in place. The vulnerability enables full remote code execution capabilities if the attacker successfully injects malicious commands through this unauthorized channel, effectively granting them root-level access to the operating system of the network infrastructure component.
The operational impact of this vulnerability is severe and wide-ranging for enterprise networks relying on Cisco IOS XE platforms. An unauthenticated attacker can gain complete control over the affected device, leading to a total compromise of confidentiality, integrity, and availability. This includes the ability to exfiltrate sensitive configuration data, modify routing tables to facilitate man-in-the-middle attacks, install persistent backdoors, or disrupt network services by shutting down critical processes. In large-scale deployments, this could lead to widespread network outages or serve as a pivot point for lateral movement within an internal network segment. The attack vector is classified as remote and requires no user interaction, making it highly scalable and dangerous in environments where devices are exposed to untrusted networks or poorly segmented VLANs.
In terms of threat modeling, this vulnerability maps directly to the MITRE ATT&CK framework technique T1078: Valid Accounts, specifically under the sub-technique of using default credentials or bypassing authentication mechanisms. It also relates to T1546.003: Windows or Linux Service Extensions, as it involves manipulating a system service for unauthorized access. The exploitation does not require complex payload delivery beyond standard network packets, lowering the barrier to entry for attackers and increasing the likelihood of automated scanning and exploitation attempts in the wild.
To mitigate this risk, organizations must immediately apply the vendor-provided software updates that address these authentication flaws. It is imperative to verify that all affected Cisco IOS XE versions are patched to the latest recommended release. In addition to patching, network segmentation strategies should be reviewed to ensure that management interfaces and services like CDP Coordinator are not exposed to untrusted zones. Implementing strict access control lists on switch ports connected to potentially vulnerable devices can limit exposure by restricting Layer 2 traffic sources. Furthermore, disabling unnecessary protocols such as CDP on edge interfaces where they are not required reduces the attack surface significantly. Continuous monitoring for anomalous network activity and regular audits of service configurations will help detect potential exploitation attempts early and maintain a robust security posture against similar access control bypasses.