CVE-2026-64083: In the Linux kernel, the following vulnerability has been resolved: hwmon: (pmbus/adm1266) reject short block-read responses in the GPIO accessors a...

Description

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.

Metrics

EPSS Probability

0.18%

8.3th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

Vendor	Product	Versions
Linux	Linux	>= d98dfad35c38c037b37c4adc99df01da571031a5, < fd9196aad9e5a3845cea17de3405ebc700382142; >= d98dfad35c38c037b37c4adc99df01da571031a5, < ee4799becf7d2af3778007e22c2e55c4009a49c7; >= d98dfad35c38c037b37c4adc99df01da571031a5, < c603b6c6840ac0c6285f5eefea0de6242710af21; >= d98dfad35c38c037b37c4adc99df01da571031a5, < a2d1c819348b36fccbbfcf37c5fa7a50a9b4528f; >= d98dfad35c38c037b37c4adc99df01da571031a5, < ae25cf2ea9ebd06d7ad416647dbdc7b5d0172946; >= d98dfad35c38c037b37c4adc99df01da571031a5, < eb3cd9bb590460c6127145cb245be925d23f5232; >= d98dfad35c38c037b37c4adc99df01da571031a5, < 64fa9328948ddcc0f7f3c23ea1756c126d9dffac; >= d98dfad35c38c037b37c4adc99df01da571031a5, < a7232f68c43ca62f545049b7f5fbfc75137b843b
Linux	Linux	5.10

References

Timeline

Published: Jul 19, 2026
Last Modified: Jul 30, 2026
Status: Awaiting Analysis

Frequently Asked Questions

What is CVE-2026-64083?

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.

How severe is CVE-2026-64083?

Severity scoring for CVE-2026-64083 is pending analysis. The EPSS model estimates a 0.18% probability of exploitation in the next 30 days.

How do I fix CVE-2026-64083?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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