CVE-2023-53203 in Linux
Summary
by MITRE • 09/15/2025
In the Linux kernel, the following vulnerability has been resolved:
wifi: mt76: mt7996: rely on mt76_connac2_mac_tx_rate_val
In order to fix a possible NULL pointer dereference in mt7996_mac_write_txwi() of vif pointer, export mt76_connac2_mac_tx_rate_val utility routine and reuse it in mt7996 driver.
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Analysis
by VulDB Data Team • 01/10/2026
The vulnerability CVE-2023-53203 addresses a critical NULL pointer dereference issue within the Linux kernel's wireless networking subsystem, specifically affecting the MediaTek mt7996 wireless driver implementation. This flaw exists in the mt76 wireless driver framework which supports various MediaTek wireless chipsets including the mt7996 model used in modern wireless networking devices. The vulnerability stems from improper handling of wireless interface pointers during transmission rate calculation operations, creating a potential crash condition that could be exploited by malicious actors to disrupt wireless connectivity or potentially escalate privileges.
The technical root cause of this vulnerability lies in the mt7996_mac_write_txwi() function where a vif pointer is accessed without proper validation, leading to a NULL pointer dereference scenario. This type of error represents a classic software flaw that falls under CWE-476 which specifically addresses NULL pointer dereference conditions. The mt76 wireless driver framework employs a modular architecture where different chipset implementations share common utility functions, and the fix involves exporting the mt76_connac2_mac_tx_rate_val routine to provide consistent rate calculation functionality across different driver variants. This utility function handles the conversion of transmission rates from internal representations to hardware-specific values, ensuring proper parameter validation before any pointer operations occur.
The operational impact of this vulnerability extends beyond simple system instability as it affects wireless networking reliability in devices running Linux kernel versions containing the affected mt76 driver code. When exploited, the NULL pointer dereference could cause the wireless subsystem to crash, resulting in complete loss of wireless connectivity for affected devices. This disruption affects not only personal computing devices but also enterprise networking equipment, IoT devices, and embedded systems that rely on MediaTek wireless chipsets. The vulnerability particularly impacts systems where wireless interfaces are actively used for data transmission, as the crash typically occurs during normal operation when transmission rate calculations are performed.
Security implications of CVE-2023-53203 align with ATT&CK technique T1499.001 which involves network denial of service attacks. While the immediate impact appears to be a system crash rather than direct privilege escalation, the vulnerability could potentially be leveraged in broader attack scenarios where sustained disruption of wireless services creates opportunities for additional exploitation. The fix implemented involves code refactoring to standardize rate calculation operations across driver variants, promoting better code reuse and reducing the likelihood of similar issues in other wireless chipset implementations within the same driver framework. This approach follows security best practices by ensuring proper input validation and eliminating potential code paths that could lead to pointer dereference errors.
The resolution of CVE-2023-53203 demonstrates the importance of maintaining consistent software quality standards across complex driver frameworks, particularly those supporting multiple hardware variants. By exporting the mt76_connac2_mac_tx_rate_val utility function, the fix ensures that all driver variants within the mt76 framework maintain consistent behavior for transmission rate calculations. This approach reduces code duplication while improving overall system stability and security posture. The vulnerability highlights the critical need for thorough testing of driver code paths, particularly those involving pointer operations and hardware interaction scenarios. Organizations should prioritize updating their Linux kernel versions to include this fix, especially in environments where wireless network reliability is critical for business operations. The mitigation strategy focuses on applying the kernel update that includes the corrected driver implementation, which provides the exported utility function with proper NULL pointer validation and prevents the crash condition from occurring during normal wireless operation.