In the Linux kernel, the following vulnerability has been resolved:

hwmon: (pmbus/adm1266) widen blackbox-info buffer to I2C_SMBUS_BLOCK_MAX

adm1266_nvmem_read_blackbox() declares a 5-byte stack buffer and
passes it to i2c_smbus_read_block_data() to retrieve the 4-byte
BLACKBOX_INFO response. i2c_smbus_read_block_data() does not honour
caller buffer sizes -- it memcpy()s data.block[0] bytes from the
SMBus transaction (where data.block[0] is the length byte returned by
the slave device, up to I2C_SMBUS_BLOCK_MAX = 32):

memcpy(values, &data.block[1], data.block[0]);

If the device returns any block length above 5, the call overflows
the caller's 5-byte stack buffer before the post-call

if (ret != 4)
return -EIO;

check has a chance to reject the response.

Widen the local buffer to I2C_SMBUS_BLOCK_MAX so the helper has room
for any well-formed SMBus block response, matching the convention used
by the other i2c_smbus_read_block_data() callers in this driver.

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Sun, 19 Jul 2026 16:15:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: hwmon: (pmbus/adm1266) widen blackbox-info buffer to I2C_SMBUS_BLOCK_MAX adm1266_nvmem_read_blackbox() declares a 5-byte stack buffer and passes it to i2c_smbus_read_block_data() to retrieve the 4-byte BLACKBOX_INFO response. i2c_smbus_read_block_data() does not honour caller buffer sizes -- it memcpy()s data.block[0] bytes from the SMBus transaction (where data.block[0] is the length byte returned by the slave device, up to I2C_SMBUS_BLOCK_MAX = 32): memcpy(values, &data.block[1], data.block[0]); If the device returns any block length above 5, the call overflows the caller's 5-byte stack buffer before the post-call if (ret != 4) return -EIO; check has a chance to reject the response. Widen the local buffer to I2C_SMBUS_BLOCK_MAX so the helper has room for any well-formed SMBus block response, matching the convention used by the other i2c_smbus_read_block_data() callers in this driver.
Title hwmon: (pmbus/adm1266) widen blackbox-info buffer to I2C_SMBUS_BLOCK_MAX
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
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cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-07-19T15:40:29.676Z

Reserved: 2026-07-19T07:54:57.036Z

Link: CVE-2026-64135

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