CVE-2026-95861 in Dream Machines
Summary
by MITRE • 09/22/2026
A malicious actor with access to the network could exploit an Uncontrolled Recursion vulnerability found in certain UniFi gateway devices to execute a Denial of Service (DoS) attack on the device.
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Analysis
by VulDB Data Team • 09/22/2026
The identified security flaw represents a critical infrastructure risk affecting specific models within the Ubiquiti UniFi gateway product line, classified technically as an uncontrolled recursion vulnerability. This type of defect typically arises when software logic fails to properly validate input parameters or manage state transitions during recursive function calls, leading to infinite loops that consume system resources exponentially rather than linearly. In the context of network gateways, which serve as the primary choke point for traffic between internal local area networks and external wide area networks, such a flaw is particularly dangerous because it targets core routing or management plane processes. A malicious actor who has gained access to the network, whether through compromised credentials, physical proximity in an unsecured environment, or exploitation of other lower-severity vulnerabilities that allow lateral movement, can trigger this recursive loop by sending specially crafted packets or requests to vulnerable endpoints. The execution of these malformed inputs causes the device's central processing unit and memory allocation mechanisms to become overwhelmed as they attempt to process nested function calls without a proper termination condition or depth limit.
From an operational perspective, the immediate impact of exploiting this vulnerability is a severe Denial of Service condition that effectively bricks the gateway for legitimate users. As the CPU utilization spikes toward one hundred percent due to the infinite recursion, the device loses its ability to perform essential routing functions, including packet forwarding, NAT translation, and DHCP lease management. This results in a complete loss of connectivity for all devices connected to the network behind the affected gateway. Unlike resource exhaustion attacks that might degrade performance gradually, uncontrolled recursion often leads to an immediate system crash or requires a hard reboot to restore functionality, causing significant downtime for businesses or households relying on continuous internet access. The attacker does not need elevated privileges beyond basic network reachability if the vulnerable service is exposed without authentication, although most UniFi devices require some level of initial access, making this attack vector relevant primarily to insiders or attackers who have already breached perimeter defenses.
This vulnerability aligns closely with Common Weakness Enumeration identifier CWE-675, which describes operations on data with insufficiently restricted recursion depth, and also relates to CWE-400 concerning uncontrolled resource consumption. In the context of the MITRE ATT&CK framework for enterprise security, this exploitation technique falls under the Tactic Impact, specifically within the subtechnique of Service Stop or Resource Hijacking. The attacker's objective is not data exfiltration but rather disruption of availability, which can be a precursor to more sophisticated attacks such as ransomware deployment during periods of organizational vulnerability and confusion, or simply an act of sabotage. Understanding this behavior helps security teams identify anomalous CPU spikes on network devices that do not correlate with normal traffic patterns, serving as an indicator of compromise for recursive DoS attempts.
Mitigation strategies must focus primarily on software remediation through vendor-provided patches. Administrators should immediately verify the firmware version running on all UniFi gateways in their environment and apply any available updates released by Ubiquiti that address this specific recursion flaw. In scenarios where patching is not immediately feasible due to operational constraints or lack of a fix, network segmentation becomes critical. Isolating management interfaces from general user traffic can prevent unauthorized actors from reaching the vulnerable services. Additionally, implementing strict access control lists on firewall rules to restrict who can communicate with the gateway's administrative ports reduces the attack surface significantly. Monitoring tools should be configured to alert on unusual CPU usage patterns or sudden drops in network throughput that coincide with specific request types, allowing for rapid incident response before total service outage occurs. Long-term resilience requires integrating these devices into a broader security posture that includes regular vulnerability scanning and strict adherence to least privilege principles for all network management interfaces.