Medium [CVE-2026-64084] (pmbus/adm1266) cap PDIO scan in get_multiple at ADM1266_PDIO_NR
This medium-severity Red Hat Linux advisory covers CVE-2026-64084.
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Summary
In the Linux kernel, the following vulnerability has been resolved: hwmon: (pmbus/adm1266) cap PDIO scan in get_multiple at ADM1266_PDIO_NR adm1266_gpio_get_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 ADM1266_PDIO_STATUS is the PMBus command code (0xE9, i.e.
233), not the number of PDIO pins.
The intended upper bound is ADM1266_GPIO_NR + ADM1266_PDIO_NR = 25. gpiolib hands in a mask sized for gc.ngpio (= 25 bits on this chip), so the iteration walks find_next_bit() 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 set_bit(gpio_nr, bits) call that writes past the end of the caller-supplied bits array too -- both out-of-bounds. Substitute ADM1266_PDIO_NR for the constant so the scan stops at the last real PDIO bit.
A flaw was found in the Linux kernel's hardware monitoring (hwmon) subsystem, specifically within the `pmbus/adm1266` driver. This vulnerability involves an out-of-bounds memory access, where the system attempts to read or write data beyond the allocated memory region.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · medium-confidence parse· fetched 6 days ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.
Official advisory · medium-confidence parse· fetched 6 days ago·verify at source
Mitigation
The source record does not include mitigation steps. That is not a statement that no fix exists — read the vendor advisory below for the authoritative guidance.
Official advisory · medium-confidence parse· fetched 6 days ago·verify at source
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