Linux Kernel adm1266 GPIO Block-Read Length Check CVE
CVE-2026-64083 Published on July 19, 2026
hwmon: (pmbus/adm1266) reject short block-read responses in the GPIO accessors
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.
Products Associated with CVE-2026-64083
stack.watch emails you whenever new vulnerabilities are published in Linux Kernel or Canonical Ubuntu Linux. Just hit a watch button to start following.
Affected Versions
Linux:- Version d98dfad35c38c037b37c4adc99df01da571031a5 and below fd9196aad9e5a3845cea17de3405ebc700382142 is affected.
- Version d98dfad35c38c037b37c4adc99df01da571031a5 and below ee4799becf7d2af3778007e22c2e55c4009a49c7 is affected.
- Version d98dfad35c38c037b37c4adc99df01da571031a5 and below c603b6c6840ac0c6285f5eefea0de6242710af21 is affected.
- Version d98dfad35c38c037b37c4adc99df01da571031a5 and below a2d1c819348b36fccbbfcf37c5fa7a50a9b4528f is affected.
- Version d98dfad35c38c037b37c4adc99df01da571031a5 and below ae25cf2ea9ebd06d7ad416647dbdc7b5d0172946 is affected.
- Version d98dfad35c38c037b37c4adc99df01da571031a5 and below eb3cd9bb590460c6127145cb245be925d23f5232 is affected.
- Version d98dfad35c38c037b37c4adc99df01da571031a5 and below 64fa9328948ddcc0f7f3c23ea1756c126d9dffac is affected.
- Version d98dfad35c38c037b37c4adc99df01da571031a5 and below a7232f68c43ca62f545049b7f5fbfc75137b843b is affected.
- Version 5.10 is affected.
- Before 5.10 is unaffected.
- Version 5.10.258, <= 5.10.* is unaffected.
- Version 5.15.209, <= 5.15.* is unaffected.
- Version 6.1.175, <= 6.1.* is unaffected.
- Version 6.6.142, <= 6.6.* is unaffected.
- Version 6.12.92, <= 6.12.* is unaffected.
- Version 6.18.34, <= 6.18.* is unaffected.
- Version 7.0.11, <= 7.0.* is unaffected.
- Version 7.1, <= * is unaffected.