CVE-2024-39464 in Linux
Summary
by MITRE • 06/25/2024
In the Linux kernel, the following vulnerability has been resolved:
media: v4l: async: Fix notifier list entry init
struct v4l2_async_notifier has several list_head members, but only waiting_list and done_list are initialized. notifier_entry was kept 'zeroed' leading to an uninitialized list_head. This results in a NULL-pointer dereference if csi2_async_register() fails, e.g. node for remote endpoint is disabled, and returns -ENOTCONN. The following calls to v4l2_async_nf_unregister() results in a NULL pointer dereference. Add the missing list head initializer.
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Analysis
by VulDB Data Team • 04/07/2026
The vulnerability CVE-2024-39464 represents a critical null pointer dereference issue within the Linux kernel's video4linux2 (v4l2) asynchronous device registration framework. This flaw exists in the media subsystem where the v4l2_async_notifier structure contains multiple list_head members that are not properly initialized during the structure's creation process. The specific issue occurs when the notifier_entry member remains uninitialized, creating a dangerous condition that can lead to system crashes and potential security implications. The vulnerability manifests when the csi2_async_register() function fails to establish asynchronous device connections, typically when remote endpoint nodes are disabled and return the -ENOTCONN error code, triggering the problematic code path.
The technical implementation flaw stems from incomplete initialization of kernel data structures within the v4l2 subsystem's asynchronous notifier framework. When the v4l2_async_notifier structure is allocated, only the waiting_list and done_list members receive proper initialization, while the notifier_entry member remains in an uninitialized state containing zeroed memory values. This uninitialized list_head structure causes subsequent operations to reference invalid memory locations, particularly when v4l2_async_nf_unregister() is called during error conditions. The null pointer dereference occurs because the kernel's list management functions attempt to traverse what appears to be a valid list head but actually contains corrupted or meaningless data, leading to immediate system termination when the invalid memory is accessed.
The operational impact of this vulnerability extends beyond simple system crashes, potentially affecting embedded systems and devices that rely heavily on video capture and processing capabilities. When triggered, the null pointer dereference can cause kernel oops messages, system panics, and complete system hangs that require manual intervention or reboot to restore functionality. This vulnerability particularly affects systems using CSI-2 (Camera Serial Interface 2) video interfaces where asynchronous device registration is critical for proper camera and sensor initialization. The flaw can be exploited by malicious actors to cause denial of service conditions, potentially disrupting video streaming services, surveillance systems, or automotive infotainment systems that depend on the Linux kernel's media subsystem for proper operation.
The vulnerability aligns with CWE-476 which identifies null pointer dereference as a critical weakness in software design, and can be mapped to ATT&CK technique T1499.004 for system shutdown/reboot attacks that leverage kernel-level vulnerabilities. The fix implemented addresses this by adding the missing list head initializer to ensure proper initialization of all list_head members within the v4l2_async_notifier structure. This remediation follows standard kernel development practices for preventing uninitialized memory access patterns and aligns with the Linux kernel's established guidelines for proper data structure initialization. The solution ensures that all list_head members maintain valid internal state regardless of execution path taken during device registration and unregistration operations, preventing the traversal of invalid memory locations that would otherwise cause system instability. Organizations should prioritize applying this patch to prevent potential exploitation and maintain system reliability in environments where video capture and processing are critical components of their infrastructure.