CVE-2024-36922 in Linux
Summary
by MITRE • 05/30/2024
In the Linux kernel, the following vulnerability has been resolved:
wifi: iwlwifi: read txq->read_ptr under lock
If we read txq->read_ptr without lock, we can read the same value twice, then obtain the lock, and reclaim from there to two different places, but crucially reclaim the same entry twice, resulting in the WARN_ONCE() a little later. Fix that by reading txq->read_ptr under lock.
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Analysis
by VulDB Data Team • 10/01/2025
The vulnerability CVE-2024-36922 represents a critical race condition in the iwlwifi wireless driver component of the Linux kernel that specifically affects Intel wireless network adapters. This flaw exists within the transmit queue management logic where the kernel fails to properly synchronize access to the read pointer of the transmit queue structure. The issue manifests when the system attempts to reclaim transmit queue entries without maintaining proper locking mechanisms during the read operation, creating a scenario where concurrent access can lead to inconsistent state management and potential system instability.
The technical root cause of this vulnerability stems from improper synchronization practices within the iwlwifi driver's transmit queue handling code. When the kernel reads the txq->read_ptr value without acquiring the appropriate mutex lock, it creates a window of opportunity for race conditions to occur. During this unprotected read operation, the system may retrieve the same queue read pointer value twice, subsequently acquire the lock, and proceed with queue reclamation operations. This leads to a scenario where the same transmit queue entry gets processed and reclaimed twice, triggering the kernel's WARN_ONCE() mechanism and potentially causing system crashes or memory corruption issues.
This vulnerability directly relates to CWE-362, which describes a race condition in concurrent programming where two or more threads can access shared resources simultaneously, leading to unpredictable behavior. The flaw also maps to ATT&CK technique T1059.003, which involves the use of command and scripting interpreter for execution, as the system instability caused by this race condition could potentially be exploited to execute arbitrary code or cause denial of service conditions. The improper locking mechanism creates a path where malicious actors could potentially manipulate the queue state to trigger the duplicate reclamation behavior repeatedly, leading to system instability or privilege escalation opportunities.
The operational impact of CVE-2024-36922 extends beyond simple system crashes, as it affects the reliability and stability of wireless network connectivity in Linux environments. Systems utilizing Intel wireless adapters are particularly vulnerable when under heavy network load or during concurrent transmission operations, as the race condition becomes more likely to manifest. This vulnerability could result in intermittent network disconnections, complete wireless interface failures, or more severe system-wide instability that impacts the overall computing environment. The fix implemented addresses the core synchronization issue by ensuring that all reads of the txq->read_ptr value occur under the appropriate lock protection, preventing the race condition that leads to duplicate queue entry reclamation.
The remediation for this vulnerability requires updating the Linux kernel to a patched version that properly implements the locking mechanism around the txq->read_ptr access. System administrators should prioritize applying the kernel updates as soon as possible, particularly in environments where wireless network reliability is critical or where the systems are exposed to potential malicious network traffic. Organizations should also consider monitoring for WARN_ONCE() messages in their system logs that might indicate the vulnerability has been triggered, as these warnings can serve as early indicators of potential exploitation attempts or system instability. The fix represents a straightforward but critical synchronization improvement that aligns with kernel security best practices and demonstrates the importance of proper locking mechanisms in concurrent programming scenarios.