CVE-2026-89943 in Linux
Summary
by MITRE • 09/16/2026
In the Linux kernel, the following vulnerability has been resolved:
ASoC: loongson: Fix error handling in ACPI property parsing
In loongson_card_parse_acpi(), the return value of device_property_read_string() for the `codec-dai-name` property was ignored. If the property is missing or invalid, an uninitialized pointer would be used later, potentially leading to undefined behavior.
Fix this by checking the return value and propagating the error appropriately.
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Analysis
by VulDB Data Team • 09/16/2026
The identified vulnerability resides within the Linux kernel's Advanced System on Chip (ASoC) subsystem, specifically in the driver implementation for Loongson platforms that utilize ACPI for hardware configuration discovery. The core technical flaw is a classic improper input validation issue where the return value of the device_property_read_string function call is not checked before proceeding with subsequent operations. In this specific context, the code attempts to retrieve the codec-dai-name property from the ACPI namespace. When this property is absent or malformed in the system firmware description, the read operation fails and returns an error code rather than a valid pointer. However, because the developer failed to inspect this return value, the execution flow continues under the false assumption that a valid string was retrieved.
This oversight leads directly to the use of an uninitialized or stale memory pointer when the driver attempts to access the codec-dai-name data later in the initialization sequence. Accessing such invalid pointers constitutes undefined behavior within the C programming language and can manifest as kernel panics, system crashes, or unpredictable runtime errors during device probing. From a security perspective, while this specific instance primarily affects availability through denial of service via crash, improper pointer handling is often a precursor to more severe exploitation vectors if memory corruption occurs. The flaw aligns with CWE-252, which covers unchecked return values, and CWE-824, regarding access to uninitialized pointers. These weaknesses represent fundamental lapses in defensive programming practices that are critical for maintaining kernel stability.
The operational impact of this vulnerability is primarily centered on system reliability rather than direct privilege escalation or data exfiltration. If a Loongson-based device lacks the specific ACPI property required by the driver, the initialization process will fail unpredictably. This can prevent audio devices from functioning correctly and may cause the entire kernel to halt if the error path triggers an invalid memory access that is not gracefully handled. For enterprise environments relying on these systems for critical infrastructure or embedded applications, such instability poses a significant risk to service continuity. The lack of proper error propagation means that higher-level subsystems cannot react appropriately to the failure, leading to cascading issues within the driver model.
To mitigate this vulnerability, the fix involves implementing rigorous return value checking for all property read operations. Developers must verify that device_property_read_string returns zero or a success code before utilizing the output pointer. If an error is detected, such as -ENODATA indicating missing data or other negative error codes, the function should immediately propagate this error up the call stack using standard kernel conventions like returning the error code directly from the probe function. This ensures that the driver initialization fails cleanly and predictably rather than proceeding with invalid state. Additionally, integrating static analysis tools configured to detect unchecked return values can help prevent similar issues in future development cycles. Adhering to these practices aligns with secure coding standards recommended by industry bodies and reduces the attack surface related to memory safety violations within the kernel space.