CVE-2026-64083: Linux Kernel

Medium severity, CVSS 5.5. EPSS: 0.2% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: hwmon: (pmbus/adm1266) reject short block-read responses in the GPIO accessors adm1266_gpio_get() and adm1266_gpio_get_multiple() both compose the pin-status word as pins_status = read_buf[0] + (read_buf[1] << 8); right after i2c_smbus_read_block_data(), guarding only against an error return. A well-behaved device returns 2 bytes for GPIO_STATUS/PDIO_STATUS, but the helper happily reports a 0- or 1-byte response too. If the device returns 0 bytes, both read_buf slots are uninitialized stack memory; if it returns 1 byte, read_buf[1] is. The composed value then flows through set_bit() into the caller's *bits in adm1266_gpio_get_multiple(), or into the return value of adm1266_gpio_get(), and ends up in userspace via gpiolib (sysfs and the char-dev ioctls). That leaks a few bits of kernel stack per request on any device whose firmware glitch, bus error, or hostile slave produces a short block-read response. Add the missing length check to both call sites and surface a short response as -EIO.

Affected products

• Linux Linux Kernel: from 5.10, before 5.10.258 (fixed in 5.10.258); from 5.11, before 5.15.209 (fixed in 5.15.209); from 5.16, before 6.1.175 (fixed in 6.1.175); from 6.2, before 6.6.142 (fixed in 6.6.142); from 6.7, before 6.12.92 (fixed in 6.12.92); from 6.13, before 6.18.34 (fixed in 6.18.34); …

Published 2026-07-19. Last modified 2026-09-03.