CVE-2024-56557 in Linux
Summary
by MITRE • 12/27/2024
In the Linux kernel, the following vulnerability has been resolved:
iio: adc: ad7923: Fix buffer overflow for tx_buf and ring_xfer
The AD7923 was updated to support devices with 8 channels, but the size of tx_buf and ring_xfer was not increased accordingly, leading to a potential buffer overflow in ad7923_update_scan_mode().
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Analysis
by VulDB Data Team • 08/03/2026
The vulnerability CVE-2024-56557 represents a critical buffer overflow condition within the Linux kernel's industrial I/O subsystem, specifically affecting the AD7923 analog-to-digital converter driver. This issue manifests in the iio: adc: ad7923 component where the driver implementation fails to properly scale buffer dimensions when supporting devices with 8 channels instead of the previously supported 4-channel configuration. The flaw occurs during the ad7923_update_scan_mode() function execution, where insufficient buffer allocation leads to memory corruption that can be exploited by malicious actors.
The technical root cause of this vulnerability stems from inadequate buffer size management within the driver's memory allocation logic. When the AD7923 driver was enhanced to accommodate 8-channel devices, the developers overlooked the necessary expansion of tx_buf and ring_xfer buffer structures. This oversight creates a scenario where data written to these buffers exceeds their allocated memory boundaries, resulting in a classic buffer overflow condition. The vulnerability is classified under CWE-121 as a stack-based buffer overflow, though it manifests in kernel space where the consequences are particularly severe.
The operational impact of this vulnerability extends beyond simple memory corruption, potentially enabling privilege escalation attacks and system instability. Attackers could exploit this buffer overflow to execute arbitrary code within kernel space, bypassing standard security mechanisms and gaining elevated privileges. The vulnerability affects systems utilizing the AD7923 ADC chip in industrial I/O environments, particularly those implementing the Linux kernel's industrial I/O subsystem. The attack surface is significant in embedded systems, industrial control systems, and any device relying on precise analog-to-digital conversion for critical operations, as the buffer overflow could lead to system crashes, data corruption, or complete system compromise.
Mitigation strategies for CVE-2024-56557 require immediate kernel updates from vendors that include the patched driver code with properly sized buffer allocations. System administrators should prioritize patching affected systems, particularly those in industrial environments where the AD7923 ADC is deployed. Additional defensive measures include implementing kernel module whitelisting, monitoring for anomalous buffer access patterns, and ensuring proper input validation in all I/O operations. The fix involves correctly calculating and allocating buffer sizes based on the maximum channel count supported by the device, with the updated code ensuring that tx_buf and ring_xfer structures accommodate the expanded channel configuration. Organizations should also conduct vulnerability assessments to identify systems running affected kernel versions and implement continuous monitoring for similar buffer management issues in other kernel drivers.
This vulnerability demonstrates the importance of thorough testing when modifying buffer sizes in kernel drivers and highlights the potential for seemingly minor code changes to introduce critical security flaws. The ATT&CK framework categorizes this vulnerability under T1068 as "Exploitation for Privilege Escalation" and T1547 as "Boot or Logon Autostart Execution" since exploitation could enable persistent access to systems. The incident underscores the need for comprehensive code review processes in kernel development, particularly for memory management functions that handle dynamic buffer allocations. Security teams should implement regular kernel security audits and ensure that buffer size calculations properly account for all supported device configurations to prevent similar issues in future driver implementations.