CVE-2024-47721 in Linux
Summary
by MITRE • 10/21/2024
In the Linux kernel, the following vulnerability has been resolved:
wifi: rtw89: remove unused C2H event ID RTW89_MAC_C2H_FUNC_READ_WOW_CAM to prevent out-of-bounds reading
The handler of firmware C2H event RTW89_MAC_C2H_FUNC_READ_WOW_CAM isn't implemented, but driver expects number of handlers is NUM_OF_RTW89_MAC_C2H_FUNC_WOW causing out-of-bounds access. Fix it by removing ID.
Addresses-Coverity-ID: 1598775 ("Out-of-bounds read")
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Analysis
by VulDB Data Team • 01/19/2026
The vulnerability described in CVE-2024-47721 resides within the Linux kernel's wireless networking subsystem, specifically affecting the rtw89 driver that manages Realtek wireless adapters. This issue represents a classic out-of-bounds memory access flaw that occurs when the driver attempts to process firmware events without proper validation of event identifiers. The vulnerability stems from a mismatch between the expected number of firmware event handlers and the actual implementation, creating a scenario where the driver's memory management logic can access memory locations beyond the allocated bounds. The affected driver component is responsible for handling wireless communication events and maintaining power management states, particularly in wake-on-wireless (WOW) scenarios where the system remains in low-power mode while monitoring for specific network events.
The technical flaw manifests through the presence of an unused firmware event ID constant RTW89_MAC_C2H_FUNC_READ_WOW_CAM within the driver's event handling framework. While the driver maintains an array or table structure that expects NUM_OF_RTW89_MAC_C2H_FUNC_WOW handlers, the actual implementation does not include a handler for this specific event ID. This discrepancy creates a scenario where the driver's event processing loop attempts to access memory locations corresponding to the non-existent handler, resulting in out-of-bounds read operations that can potentially expose sensitive memory regions or cause system instability. The vulnerability is classified as an out-of-bounds read according to Coverity static analysis, which identifies the flaw through automated code inspection tools that detect potential memory access violations.
The operational impact of this vulnerability extends beyond simple memory corruption, as it represents a potential attack surface for malicious actors who could exploit the out-of-bounds read to gain unauthorized access to kernel memory spaces. This type of vulnerability could enable privilege escalation attacks where an attacker with local access or specific network conditions might manipulate firmware events to trigger the memory access violation and potentially execute arbitrary code within kernel space. The risk is particularly elevated in wireless networking environments where firmware updates and event handling are frequent operations, making the system susceptible to exploitation through crafted wireless traffic or firmware interactions. According to CWE classification, this vulnerability maps to CWE-125: Out-of-bounds Read, which specifically addresses situations where programs access memory locations beyond the bounds of allocated buffers. The ATT&CK framework would categorize this under T1068: Exploitation for Privilege Escalation, as successful exploitation could allow attackers to gain kernel-level privileges.
Mitigation strategies for this vulnerability primarily focus on the immediate removal of the unused event ID from the driver's processing framework, effectively eliminating the out-of-bounds access condition. System administrators should ensure that all wireless networking drivers are updated to versions containing the fix, particularly in environments where wireless connectivity is critical and where security considerations are paramount. The fix implemented in the patch removes the problematic event ID constant from the driver's event handling table, preventing the driver from attempting to process non-existent handlers and thereby eliminating the potential for out-of-bounds memory access. Regular kernel updates and wireless driver maintenance are essential practices to prevent similar vulnerabilities from accumulating in the system, as this type of issue often occurs due to incomplete code removal or inadequate testing of event handling frameworks in complex networking subsystems. The solution aligns with secure coding practices that emphasize the importance of maintaining consistency between declared capabilities and actual implementations, particularly in kernel-level code where memory safety is critical for overall system security.