CVE-2026-18909 in ELAN Smart-Pad
Summary
by MITRE • 08/06/2026
A stack-based buffer overflow vulnerability exists in ELAN Microelectronics Corp. ELAN Smart-Pad on Windows (ETD.sys and ETDSMBus.sys). During Intel SMBus recovery, ETDSMBus.sys does not enforce an upper-bound check on the hardware-derived report count, allowing an out-of-range value to be forwarded to ETD.sys where it is used as a loop counter for a stack buffer copy without destination size validation. A local attacker with standard user privileges can trigger a kernel bugcheck (BSOD 0xF7 DRIVER_OVERRAN_STACK_BUFFER), resulting in denial of service. This issue affects ELAN Smart-Pad through ETD24.21.52.3.
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Analysis
by VulDB Data Team • 08/06/2026
This vulnerability represents a critical stack-based buffer overflow in ELAN Microelectronics Corp.'s Smart-Pad driver components ETD.sys and ETDSMBus.sys on Windows systems. The flaw manifests during Intel SMBus recovery operations when ETDSMBus.sys fails to implement proper upper-bound validation on hardware-derived report counts. This absence of input sanitization allows malformed or excessive values to propagate into the kernel-level ETD.sys component where they are consumed as loop counters for stack buffer operations. The vulnerability stems from inadequate bounds checking mechanisms and improper parameter validation within the driver's communication protocols, creating an exploitable condition that directly impacts system stability and security.
The technical execution of this vulnerability follows a well-defined attack path that begins with a local attacker leveraging standard user privileges to trigger the problematic code path. During Intel SMBus recovery processes, the ETDSMBus.sys component receives hardware-derived report count values that should be validated against predetermined maximum limits. Without proper boundary enforcement, an attacker can manipulate these values to exceed normal operational parameters, causing the downstream ETD.sys driver to process invalid loop counters. The stack buffer copy operation in ETD.sys lacks destination size validation, creating a classic buffer overflow scenario where the out-of-range counter value directly influences how many iterations the vulnerable code performs during memory copying operations.
The operational impact of this vulnerability extends beyond simple denial of service to potentially compromise system integrity and availability. When the malformed loop counter causes the kernel to exceed stack buffer boundaries, it triggers a kernel bugcheck resulting in blue screen of death (BSOD) with error code 0xF7 DRIVER_OVERRAN_STACK_BUFFER. This specific error code indicates that a driver has corrupted the stack buffer, which can lead to system crashes, forced reboots, and complete service disruption for the affected Smart-Pad device. The local privilege requirement means that while exploitation does not require administrative access, it still provides significant operational disruption to users who rely on these touchpad devices.
This vulnerability aligns with CWE-129, which describes improper validation of length of input buffers, and CWE-787, which addresses out-of-bounds write operations. The attack pattern follows the ATT&CK technique T1068, specifically targeting local privilege escalation through kernel-mode exploitation, though in this case it manifests as a denial of service rather than privilege elevation. The flaw demonstrates poor input validation practices and inadequate defensive programming measures in kernel drivers, which are critical system components that must maintain strict boundaries and validate all incoming data. The vulnerability represents a fundamental breakdown in the driver's security model where hardware-generated values are trusted without proper sanitization, creating an attack surface that can be exploited to cause system instability.
Mitigation strategies should focus on immediate driver updates from ELAN Microelectronics to address the bounds checking deficiencies in both ETD.sys and ETDSMBus.sys components. System administrators should implement monitoring for BSOD 0xF7 errors related to these drivers and consider disabling unnecessary SMBus recovery operations when possible. The recommended approach involves verifying that hardware-derived values are properly bounded before being used in kernel-level loop counters and implementing comprehensive input validation at all levels of the driver stack. Additionally, organizations should conduct vulnerability assessments to identify other potentially affected ELAN Smart-Pad devices and ensure proper patch management protocols are in place to address similar issues across their computing environments.