CVE-2026-97538 in Linux
Summary
by MITRE • 09/25/2026
In the Linux kernel, the following vulnerability has been resolved:
hwmon: (asus_rog_ryujin) Validate HID report lengths
rog_ryujin_raw_event() parses response headers and payload fields without first checking that they are present in the received report. A short report can therefore make the driver consume uninitialized bytes from the HID transport buffer and expose them as sensor values through sysfs.
Validate the response header and the fields used by each response type before parsing them.
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Analysis
by VulDB Data Team • 09/25/2026
The vulnerability identified within the Linux kernel's hwmon subsystem, specifically affecting the ASUS ROG Ryujin driver, represents a critical input validation failure that leads to information disclosure through uninitialized memory exposure. This flaw resides in the rog_ryujin_raw_event function, which is responsible for parsing response headers and payload fields from Human Interface Device reports received by the system. The core technical deficiency lies in the absence of length checks before accessing data structures within these HID transport buffers. When a device or malicious actor sends a report that is shorter than expected, the driver proceeds to parse fields without verifying their presence or boundaries. Consequently, the code reads beyond the valid end of the received packet, consuming uninitialized bytes from the surrounding memory space in the kernel's buffer allocation.
This out-of-bounds read condition allows sensitive data residing adjacent to the HID report buffer to be interpreted as sensor values and subsequently exposed through the sysfs interface. Sysfs serves as a primary mechanism for user-space applications to interact with hardware monitoring features, meaning that this vulnerability effectively bridges the gap between low-level kernel memory operations and high-level application access points. An attacker who can trigger the reception of malformed or truncated HID reports could potentially leak kernel stack contents, heap data, or other sensitive information from adjacent allocations. This type of flaw is classified under CWE-125, which denotes Out-of-bounds Read vulnerabilities, as it involves reading memory beyond allocated boundaries due to insufficient boundary checks on input lengths.
From an operational perspective, the impact extends beyond simple data leakage. The exposure of uninitialized kernel memory can provide attackers with valuable intelligence for further exploitation attempts, such as bypassing security mitigations like KASLR or identifying valid pointers within the kernel address space. Furthermore, depending on how the leaked bytes are interpreted by subsequent processing logic, there is a potential risk of causing undefined behavior that could lead to system instability or crashes, although the primary vector here remains information disclosure. The vulnerability highlights the risks associated with trusting hardware input without rigorous validation, particularly in drivers handling complex protocol implementations like those found in gaming peripherals and RGB lighting controllers.
To mitigate this vulnerability, it is imperative to implement strict length validation for all incoming HID reports before any parsing logic is executed. Developers must verify that the received report contains at least the minimum number of bytes required by the response header and each specific payload field type defined in the driver's protocol specification. This defensive programming approach ensures that access to buffer indices remains within safe, allocated limits regardless of the actual data length provided by the device or an attacker. Additionally, integrating fuzzing tests into the development lifecycle for HID drivers can help identify similar boundary conditions early. System administrators should ensure their kernels are updated with patches addressing this specific hwmon driver flaw to prevent unauthorized access to kernel memory via sysfs interfaces associated with ASUS ROG Ryujin devices. This issue aligns with ATT&CK technique T1083, which covers File and Directory Discovery, as the exploitation vector leverages standard system information retrieval mechanisms to exfiltrate data that was not intended for public consumption.