PT-2026-61403 · Linux · Linux

CVE-2026-64086 · Published 2026-07-19 · Updated 2026-07-19

Mitre

CVSS v3.1

7.8

High

Base vector

AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

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.

Fix

Related Identifiers

CVE-2026-64086

Affected Products

Linux

References · 9

• https://nvd.nist.gov/vuln/detail/CVE-2026-64086 · Security Note
• https://git.kernel.org/stable/c/397d3f523bfff2f4e3dacf9b1339bd76dc207f78 · Note
• https://git.kernel.org/stable/c/d94ceb16e55b6d8019ab069e357c76ac42f0ffbc · Note
• https://git.kernel.org/stable/c/528a9f88e88502d0c2f2052a279415074cd83715 · Note
• https://git.kernel.org/stable/c/487566cb1ccdf3756fdd7bf8d875e612ff3169bb · Note
• https://git.kernel.org/stable/c/472744f69d25a2d5111ad62f1d62579dce2c13c8 · Note
• https://git.kernel.org/stable/c/2279c342d94eca225bf9f301c8806a05a1c81619 · Note
• https://git.kernel.org/stable/c/bd5be3fa5de6dbf61f1b3cec6b79c2c2f8065694 · Note
• https://git.kernel.org/stable/c/a6c802145a8de0830bca803c6d415f7e9e683624 · Note