Linux kernel ADM1266 SMBus block read stack overflow
CVE-2026-64135 Published on July 19, 2026
hwmon: (pmbus/adm1266) widen blackbox-info buffer to I2C_SMBUS_BLOCK_MAX
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.
Products Associated with CVE-2026-64135
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Affected Versions
Linux:- Version 15609d1893020436e1e8ccfd9ded774a96dd17a2 and below 33251abb9c9dd62943be76f0427c5527ee39188f is affected.
- Version 15609d1893020436e1e8ccfd9ded774a96dd17a2 and below ba09f4baa5bd96c5d26c942defa546a72dbbe5bf is affected.
- Version 15609d1893020436e1e8ccfd9ded774a96dd17a2 and below 6ed16a40b162e9d87d9ac8bed4d7f0e3e807700e is affected.
- Version 15609d1893020436e1e8ccfd9ded774a96dd17a2 and below 0dbf64c502443c08c2e28a77ecbfcc5479d93228 is affected.
- Version 15609d1893020436e1e8ccfd9ded774a96dd17a2 and below 2b7a698d5093b548c464828d984f05ced5f3fd2a is affected.
- Version 15609d1893020436e1e8ccfd9ded774a96dd17a2 and below ca560f7566df7e2826c2999e959e6b94eb938f76 is affected.
- Version 15609d1893020436e1e8ccfd9ded774a96dd17a2 and below 7f705e581ef3e6bb308a121a89adf5237d968204 is affected.
- Version 15609d1893020436e1e8ccfd9ded774a96dd17a2 and below eee213daa1e1b402eb631bcd1b8c5aa340a6b081 is affected.
- Version 5.10 is affected.
- Before 5.10 is unaffected.
- Version 5.10.258, <= 5.10.* is unaffected.
- Version 5.15.209, <= 5.15.* is unaffected.
- Version 6.1.175, <= 6.1.* is unaffected.
- Version 6.6.142, <= 6.6.* is unaffected.
- Version 6.12.92, <= 6.12.* is unaffected.
- Version 6.18.34, <= 6.18.* is unaffected.
- Version 7.0.11, <= 7.0.* is unaffected.
- Version 7.1, <= * is unaffected.