CVE-2026-64084 hwmon: (pmbus/adm1266) cap PDIO scan in get_multiple at ADM1266_PDIO_NR
Out-of-bounds read and write in the ADM1266 PMBus driver due to incorrect loop bounds, potentially allowing local attackers to execute code or escalate privileges.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-64084?
CVE-2026-64084 is a high-severity memory corruption vulnerability in Linux kernel, published on 19 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
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.
Weakness: CWE-787
Which versions are affected by CVE-2026-64084?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-64084?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-64084 being exploited?
There is no known exploitation of CVE-2026-64084 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-64084, DEBIAN-CVE-2026-64084, GHSA-m232-p3mf-6xc5, UBUNTU-CVE-2026-64084.