Interrupt Handler Vulnerability in Linux Kernel for MCP23S08 Chip

CVE-2026-43087

What is CVE-2026-43087?

A vulnerability has been identified in the Linux kernel involving the MCP23S08 chip, where the interrupt-on-change feature can be enabled for certain pins during initialization. If a reboot occurs, this can lead to the generation of interrupts for pins lacking registered nested handlers. Consequently, this may result in a kernel crash due to an attempt to access unreadable memory. The issue originated with a kernel commit that altered the behavior of the interrupt handler, exposing the vulnerability that was previously dormant. The recommended fix involves disabling all pin interrupts during the initialization process.

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