CVE-2025-39690 in Linux
Summary
by MITRE • 09/05/2025
In the Linux kernel, the following vulnerability has been resolved:
iio: accel: sca3300: fix uninitialized iio scan data
Fix potential leak of uninitialized stack data to userspace by ensuring that the `channels` array is zeroed before use.
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Analysis
by VulDB Data Team • 02/09/2026
The vulnerability CVE-2025-39690 addresses a critical security issue within the Linux kernel's industrial I/O subsystem, specifically affecting the sca3300 accelerometer driver. This flaw resides in the iio subsystem's handling of scan data for accelerometer sensors, representing a classic case of uninitialized memory exposure that could potentially lead to information disclosure. The vulnerability impacts systems utilizing the sca3300 sensor hardware through the Linux kernel's I/O infrastructure, where improper memory initialization creates a pathway for sensitive data leakage.
The technical root cause of this vulnerability stems from the improper initialization of the channels array within the sca3300 driver implementation. When processing sensor data, the driver fails to properly zero out the scan data buffer before populating it with actual sensor readings, leaving residual stack memory contents accessible to userspace applications. This uninitialized memory typically contains remnants of previous operations, including potentially sensitive kernel data, debug information, or other system state information that should remain confidential. The flaw specifically affects the iio subsystem's channel scanning mechanism, where the driver's scan buffer is not adequately cleared before data collection begins.
The operational impact of this vulnerability extends beyond simple information disclosure, as it represents a potential vector for privilege escalation or reconnaissance activities. Attackers could exploit this weakness to extract kernel memory contents, potentially including cryptographic keys, session tokens, or other sensitive data that might be present in the uninitialized memory regions. The vulnerability affects systems running affected Linux kernel versions where the iio subsystem processes data from sca3300 accelerometer devices, particularly in industrial automation, embedded systems, or IoT deployments where these sensors are commonly utilized. This exposure could enable adversaries to gain insights into system internals or potentially aid in more sophisticated attacks targeting kernel memory layouts.
Security mitigations for CVE-2025-39690 involve applying the kernel patch that ensures proper zero-initialization of the channels array before data processing begins. This fix aligns with the principle of least privilege and secure coding practices, specifically addressing CWE-457: Use of Uninitialized Variable, which is a fundamental security principle in software development. The remediation follows established security guidelines for memory management in kernel space, where proper initialization of all data structures is essential to prevent information leakage. Organizations should prioritize applying the kernel updates containing this fix and implement comprehensive monitoring to detect any potential exploitation attempts. The fix demonstrates the importance of proper memory management in kernel drivers and aligns with ATT&CK technique T1005: Data from Local System, which focuses on collecting information from compromised systems. This vulnerability highlights the critical need for robust input validation and memory initialization practices in kernel-level code, particularly within hardware abstraction layers that interface directly with physical sensors and device drivers.