CVE-2022-49968 in Linux
Summary
by MITRE • 06/18/2025
In the Linux kernel, the following vulnerability has been resolved:
ieee802154/adf7242: defer destroy_workqueue call
There is a possible race condition (use-after-free) like below
(FREE) | (USE) adf7242_remove | adf7242_channel cancel_delayed_work_sync | destroy_workqueue (1) | adf7242_cmd_rx | mod_delayed_work (2) |
The root cause for this race is that the upper layer (ieee802154) is unaware of this detaching event and the function adf7242_channel can be called without any checks.
To fix this, we can add a flag write at the beginning of adf7242_remove and add flag check in adf7242_channel. Or we can just defer the destructive operation like other commit 3e0588c291d6 ("hamradio: defer ax25 kfree after unregister_netdev") which let the ieee802154_unregister_hw() to handle the synchronization. This patch takes the second option.
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Analysis
by VulDB Data Team • 11/30/2025
The vulnerability CVE-2022-49968 represents a critical use-after-free condition within the Linux kernel's ieee802154 subsystem, specifically affecting the adf7242 wireless driver implementation. This flaw manifests as a race condition during device removal operations where the kernel's wireless subsystem fails to properly synchronize access to shared resources between the device removal process and ongoing channel operations. The vulnerability occurs when the adf7242_remove function attempts to destroy a workqueue while another function, adf7242_channel, may still be executing and referencing freed memory structures. The race condition follows a specific temporal sequence where the device removal process cancels delayed work and destroys the workqueue, while concurrently the channel function attempts to modify workqueue operations, creating a scenario where freed memory is accessed after deallocation. This type of vulnerability falls under CWE-416, which specifically addresses use-after-free conditions, and represents a classic example of improper resource management in kernel space operations.
The technical implementation of this vulnerability stems from inadequate synchronization mechanisms within the ieee802154 wireless subsystem's device management framework. When a device is removed, the kernel must ensure that all pending operations complete before resources are freed, but the adf7242 driver lacks proper coordination between the upper layer ieee802154 framework and the lower level device operations. The adf7242_channel function can be invoked without proper checks for device detachment, creating a scenario where the function attempts to schedule work items on a workqueue that is in the process of being destroyed. This fundamental flaw in the driver's architecture violates proper kernel programming practices and creates an exploitable condition where malicious actors could potentially trigger memory corruption or privilege escalation. The vulnerability demonstrates a failure in proper device lifecycle management, where the kernel's wireless subsystem does not adequately coordinate between the network device registration and removal processes, leading to improper resource cleanup timing.
The operational impact of this vulnerability extends beyond simple memory corruption to potentially enable privilege escalation and system instability within kernel space environments. An attacker who can manipulate the timing of device removal and channel operations could potentially exploit this race condition to execute arbitrary code with kernel privileges, effectively compromising the entire system. The vulnerability affects systems running Linux kernels that include the ieee802154 subsystem with the adf7242 driver implementation, particularly those supporting 802.15.4 wireless protocols for low-power sensor networks and IoT devices. This type of vulnerability is particularly concerning in embedded systems and IoT deployments where kernel-level access is critical for maintaining system integrity and where such vulnerabilities could be exploited to gain persistent access to networked devices. The exploitation potential aligns with ATT&CK technique T1068, which covers local privilege escalation through kernel vulnerabilities, and represents a significant security risk for any system relying on wireless communication protocols in kernel space.
The resolution for CVE-2022-49968 follows a well-established pattern of kernel-level defensive programming that defers destructive operations until all pending work is completed, similar to other fixes within the Linux kernel ecosystem. The chosen mitigation strategy implements a deferment approach consistent with commit 3e0588c291d6 which handled a similar issue in the hamradio subsystem by deferring kfree operations after unregister_netdev. This solution ensures that the ieee802154_unregister_hw() function properly coordinates the synchronization between device removal and ongoing operations, allowing all pending work items to complete before resource deallocation occurs. The fix avoids the complexity of introducing additional flags and checks while maintaining the integrity of the driver's operational flow. This approach aligns with kernel security best practices that emphasize proper resource lifecycle management and synchronization, following established patterns within the Linux kernel community for handling similar race conditions. The implementation ensures that the device removal process defers the destruction of workqueues until all concurrent operations have completed, preventing the use-after-free scenario that could otherwise lead to system crashes or security exploits.