Bug 2502491 (CVE-2026-64135) - CVE-2026-64135 kernel: hwmon: (pmbus/adm1266) widen blackbox-info buffer to I2C_SMBUS_BLOCK_MAX
Summary: CVE-2026-64135 kernel: hwmon: (pmbus/adm1266) widen blackbox-info buffer to I...
Keywords:
Status: NEW
Alias: CVE-2026-64135
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
unspecified
unspecified
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
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Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-07-19 17:02 UTC by OSIDB Bzimport
Modified: 2026-07-21 05:06 UTC (History)
2 users (show)

Fixed In Version:
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Description OSIDB Bzimport 2026-07-19 17:02:17 UTC
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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