CVE-2026-64084

In the Linux kernel, the following vulnerability has been resolved:

hwmon: (pmbus/adm1266) cap PDIO scan in getmultiple at ADM1266PDIO_NR

adm1266gpioget_multiple() iterates the PDIO portion of the caller-supplied mask using

for_each_set_bit_from(gpio_nr, mask,
              ADM1266_GPIO_NR + ADM1266_PDIO_STATUS) {
    ...
}

where ADM1266PDIOSTATUS is the PMBus command code (0xE9, i.e. 233), not the number of PDIO pins. The intended upper bound is ADM1266GPIONR + ADM1266PDIONR = 25.

gpiolib hands in a mask sized for gc.ngpio (= 25 bits on this chip), so the iteration walks findnextbit() up to 242, reading up to 217 extra bits (a handful of unsigned-long words: four on 64-bit, seven on 32-bit) of whatever lives past the end of the mask in the caller's stack. Any incidental set bit in that range then drives a setbit(gpionr, bits) call that writes past the end of the caller-supplied bits array too -- both out-of-bounds.

Substitute ADM1266PDIONR for the constant so the scan stops at the last real PDIO bit.