CVE-2026-64135

Published Jul 19, 2026

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.

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References

Frequently Asked Questions

What is CVE-2026-64135? +
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.
How do I check if I'm vulnerable to CVE-2026-64135? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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