CVE-2026-98203 in Linux
Summary
by MITRE • 10/06/2026
In the Linux kernel, the following vulnerability has been resolved:
Input: soc_button_array - check btns_desc->package.count
Check that btns_desc->package.count is not 0 before accessing btns_desc->package.elements[0].
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Analysis
by VulDB Data Team • 10/06/2026
The identified vulnerability resides within the linux kernel input subsystem, specifically in the driver for the soc button array. This component is responsible for managing hardware buttons integrated into system-on-chip architectures, often found in mobile and embedded devices. The core technical flaw involves a missing bounds check on an integer value derived from device tree or firmware descriptions. Specifically, the code attempts to access the first element of an elements array using index zero without verifying that the count field associated with that package is greater than zero. This oversight creates a classic out-of-bounds read condition where the kernel dereferences memory based on uninitialized or invalid data structures provided by external sources such as device tree overlays or ACPI tables.
From a technical perspective, this flaw represents an improper input validation error where the software fails to verify that the number of elements in a collection is sufficient before accessing specific indices within that collection. In the context of common weakness enumerations, this aligns with CWE-125 which describes out-of-bounds read vulnerabilities. When btns_desc->package.count equals zero or remains uninitialized due to malformed input, the subsequent access to btns_desc->package.elements[0] reads from memory locations outside the intended bounds of the allocated array. This can lead to unpredictable behavior depending on what data resides in that adjacent memory space, potentially leaking sensitive kernel information or causing a system crash if the accessed address is unmapped.
The operational impact of this vulnerability extends beyond simple stability issues. An attacker with local access who can influence device tree parameters or ACPI tables could exploit this flaw to trigger an out-of-bounds read. While primarily classified as a denial of service vector due to potential kernel panics, such memory corruption vulnerabilities often serve as precursors to more severe exploits. By carefully crafting input that triggers the invalid memory access, an attacker might achieve arbitrary code execution if they can control the data returned by the out-of-bounds read or leverage it in conjunction with other primitives to bypass security mitigations like kASLR. This aligns with ATT&CK techniques related to initial exploitation and privilege escalation within operating systems.
Mitigation strategies for this vulnerability involve both immediate patching and long-term defensive coding practices. The primary remediation is the application of the upstream kernel fix which explicitly checks that btns_desc->package.count is not zero before proceeding with array access. System administrators should ensure their kernels are updated to versions containing this specific input validation logic. Furthermore, developers working on similar drivers should adopt stricter static analysis and runtime bounds checking mechanisms. Implementing defensive programming patterns where all external data structures are validated for integrity and size constraints prior to dereferencing pointers is essential to prevent recurrence of such out-of-bounds access issues in future kernel development cycles.