CVE-2026-98916 in Linux
Summary
by MITRE • 10/23/2026
In the Linux kernel, the following vulnerability has been resolved:
wifi: nl80211: check link is beaconing for color change
When trying to do a color change, validate that the link is beaconing first, to avoid calling the driver with an invalid link.
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Analysis
by VulDB Data Team • 10/23/2026
The Linux kernel contains a vulnerability within the wireless networking subsystem specifically affecting the nl80211 interface which handles configuration and management of IEEE 802.11 compliant devices. This flaw arises during the execution of color change operations, a mechanism used in modern Wi-Fi standards such as 802.11ax to optimize channel utilization by adjusting the primary channel segment within a basic service set. The core technical deficiency lies in the absence of a validation check prior to invoking driver-specific callbacks associated with this operation. Specifically, when an administrator or automated system requests a color change, the kernel fails to verify whether the target link is currently beaconing. Beaconing is a fundamental state where access points periodically transmit management frames to maintain network presence and synchronize clients. Without confirming that the link is actively beaconing, the kernel proceeds to pass invalid link identifiers or states down to the underlying wireless driver hardware abstraction layer.
This lack of precondition checking can lead to undefined behavior within the device driver stack. Drivers typically assume that certain operational contexts are valid when they receive commands from the upper layers of the networking subsystem. By receiving a request for a color change on a non-beaconing link, the driver may attempt to access memory structures or hardware registers associated with an inactive or improperly initialized context. This can result in kernel panics, system crashes, or data corruption within the network stack. In severe cases, if the invalid state triggers a race condition or allows for out-of-bounds memory access during subsequent processing of malformed link identifiers, it could potentially be exploited by a local user with appropriate privileges to cause a denial of service against the host system. The vulnerability highlights a critical gap in input validation at the boundary between generic kernel networking code and hardware-specific driver implementations.
From a classification perspective, this issue aligns closely with CWE-20 Improper Input Validation as the root cause is the failure to validate that the link state meets the necessary criteria before proceeding with an operation. It also relates to CWE-823 Use of Out-of-range Pointer Offset if the invalid link reference leads to incorrect memory addressing within driver structures. In terms of adversarial tactics, this vulnerability could be leveraged in a local privilege escalation or denial of service attack vector under ATT&CK technique T1059 Command and Scripting Interpreter if an attacker can trigger the condition through scripted configuration changes, though it primarily represents a stability risk rather than a direct remote exploitation path. The impact is largely confined to system availability due to potential kernel crashes triggered by local administrative actions or automated network management tools that do not adequately check link status before issuing commands.
Mitigation for this vulnerability involves applying the upstream Linux kernel patch that introduces explicit validation logic into the nl80211 color change handler. System administrators should ensure their systems are updated with the latest stable kernel versions where this fix is integrated. For environments running older kernels, temporary mitigations include restricting access to wireless configuration utilities and ensuring that network management scripts verify link beaconing status before attempting any channel or color modifications. Additionally, monitoring system logs for unexpected kernel oops messages related to nl80211 can help detect attempts to exploit this flaw in real-time until the patch is deployed. Regular auditing of wireless interface configurations and enforcing strict role-based access control on network management interfaces further reduces the attack surface associated with such local configuration vulnerabilities.