CVE-2026-64086
Received Received - Intake

Buffer Overflow in ADM1266 Linux Kernel Driver

Publication date: 2026-07-19

Last updated on: 2026-07-19

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: hwmon: (pmbus/adm1266) include PEC byte in pmbus_block_xfer read buffer adm1266_pmbus_block_xfer() sets up the read transaction with .buf = data->read_buf, .len = ADM1266_PMBUS_BLOCK_MAX + 2, but read_buf in struct adm1266_data is declared as u8 read_buf[ADM1266_PMBUS_BLOCK_MAX + 1]; For a max-length block response (length byte = 255 + up to 1 PEC byte), the i2c controller is told to write 257 bytes into a 256-byte buffer, putting one byte past the end of read_buf. The same response also makes the subsequent PEC compare if (crc != msgs[1].buf[msgs[1].buf[0] + 1]) read a byte beyond the array. Bump the read_buf declaration to ADM1266_PMBUS_BLOCK_MAX + 2 so the buffer can hold the length byte, up to 255 payload bytes, and the PEC byte the i2c_msg length already accounts for.

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Meta Information

Published
2026-07-19
Last Modified
2026-07-19
Generated
2026-07-20
AI Q&A
2026-07-19
EPSS Evaluated
N/A
NVD
CVE-2026-64086
EUVD
EUVD-2026-45659

Affected Vendors & Products

Showing 2 associated CPEs
Vendor Product Version / Range
linux_kernel linux_kernel *
linux linux_kernel *

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Exploitability

CWE
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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability is a buffer overflow issue in the Linux kernel's hwmon subsystem, specifically in the pmbus/adm1266 driver. The problem occurs when reading data from an I2C device. The driver incorrectly sets up a read buffer that is one byte too small to handle the maximum possible response size, which includes a length byte, up to 255 data bytes, and a PEC (Packet Error Code) byte. This causes the driver to write one byte past the end of the allocated buffer, leading to a potential memory corruption or crash.

Detection Guidance

This vulnerability is specific to the Linux kernel's hwmon subsystem for the adm1266 PMBus driver. Detection requires checking the kernel version and the presence of the affected driver. Use commands like 'uname -a' to check the kernel version and 'lsmod | grep adm1266' to see if the driver is loaded. If the driver is loaded and the kernel version is vulnerable, the system is affected.

Impact Analysis

If you are using a system with the affected Linux kernel version and the adm1266 hardware monitoring driver, this vulnerability could cause system instability or crashes when interacting with the adm1266 device. It may lead to unexpected behavior, data corruption, or denial of service if exploited maliciously or triggered by specific hardware responses.

Compliance Impact

This vulnerability involves a buffer overflow in the Linux kernel's hwmon subsystem for the adm1266 driver, which could lead to memory corruption or crashes. While it does not directly impact data privacy or security controls, such low-level memory issues could potentially be exploited to bypass security mechanisms or gain unauthorized access, indirectly affecting compliance with standards like GDPR or HIPAA that require robust security measures.

Mitigation Strategies

Update the Linux kernel to a patched version that includes the fix for this vulnerability. This can typically be done via your distribution's package manager (e.g., 'apt upgrade', 'yum update', or 'dnf upgrade'). After updating, reboot the system to ensure the new kernel is running.

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