CVE-2026-97450 in Linux
Summary
by MITRE • 09/24/2026
In the Linux kernel, the following vulnerability has been resolved:
ACPICA: validate handler object type in two places
ACPICA: validate handler object type in acpi_ev_has_default_handler() and acpi_ev_find_region_handler().
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Analysis
by VulDB Data Team • 09/24/2026
The Advanced Configuration and Power Interface (ACPI) subsystem within the Linux kernel relies heavily on ACPICA, a reference implementation of the ACPI specification that provides drivers for hardware configuration and power management. This specific vulnerability addresses critical input validation deficiencies in two key functions responsible for locating and managing ACPI event handlers: acpi_ev_has_default_handler() and acpi_ev_find_region_handler(). These functions are integral to the kernel's ability to interpret ACPI tables, which describe hardware components such as processors, buses, devices, and their interconnections. When the operating system boots or when dynamic power management events occur, it queries these handler objects to determine how to interact with specific hardware regions or execute predefined actions for certain types of events. The absence of rigorous type validation in these code paths creates a scenario where malformed or maliciously crafted ACPI tables can exploit this lack of verification.
The technical flaw lies in the failure to verify that the object passed into these handler lookup functions is indeed of the expected data structure type before it is dereferenced and used for further processing. In C-based kernel development, assuming an incorrect pointer type without validation often leads to undefined behavior. If a user or attacker can influence the content of ACPI tables loaded by the system, they could provide an object that does not match the anticipated handler structure. When acpi_ev_has_default_handler() or acpi_ev_find_region_handler() processes this invalid object, it may attempt to access memory offsets or fields that do not exist within the actual data layout. This mismatch typically results in a kernel panic due to an invalid memory access, effectively causing a denial of service against the entire system. In more complex scenarios involving specific hardware interactions, such incorrect pointer arithmetic could potentially lead to arbitrary code execution if the attacker can control the contents pointed to by the malformed object, although the primary immediate impact is usually stability-related rather than privilege escalation.
From an operational perspective, this vulnerability impacts systems that rely on ACPI for power management and device enumeration, which includes nearly all x86-based laptops, desktops, and many server platforms. An attacker with physical access or the ability to modify firmware NVRAM could trigger these code paths during boot sequences or by injecting malformed data through hot-plug events. The consequence is a system crash that requires a reboot, disrupting availability for critical workloads. For enterprise environments running virtualization hosts, this instability can lead to hypervisor crashes and subsequent downtime for all guest operating systems hosted on the affected machine. Furthermore, because ACPI tables are often signed but not always strictly validated against expected schema constraints by older kernel versions, the attack surface remains viable across various deployment scenarios where firmware integrity is compromised or tampered with.
Mitigation strategies primarily involve applying the upstream Linux kernel patches that introduce explicit type checking before dereferencing handler objects. System administrators should ensure their systems are updated to a version of the kernel that includes these ACPICA fixes, as they enforce strict adherence to ACPI specification requirements regarding object types. Additionally, organizations can enhance security posture by enabling Secure Boot and ensuring firmware signatures are verified during boot processes to prevent unauthorized modification of ACPI tables stored in non-volatile memory. Regular auditing of hardware compatibility lists and keeping BIOS/UEFI firmware up to date also reduces the risk associated with malformed or maliciously crafted table structures being loaded into kernel space.
This vulnerability aligns with CWE-20, Improper Input Validation, as the core issue is the failure to validate that incoming data conforms to expected structural constraints before use. It also relates to CWE-823, Use of Out-of-range Pointer Offset, because accessing fields based on incorrect type assumptions often results in calculating offsets into invalid memory regions. In terms of MITRE ATT&CK mapping, this falls under T1546.009, Event Triggered Execution: ACPI Events, as the exploitation vector involves manipulating ACPI mechanisms to trigger unintended kernel behavior. The remediation emphasizes defensive programming practices where every pointer derived from external or firmware sources must be validated against its expected type and size before any operations are performed on it, ensuring that the integrity of system-critical subsystems like power management is maintained even in the face of corrupted input data.