CVE-2026-64135 Linux CVE debrief

Who should care

Linux kernel users and administrators should be aware of this vulnerability and ensure they have the latest kernel updates applied. This vulnerability affects the hwmon: (pmbus/adm1266) driver in the Linux kernel, and users of this driver should take priority in applying the necessary updates. Additionally, vulnerability management and security teams should review the affected scope and severity to determine the necessary course of action.

Technical summary

The hwmon: (pmbus/adm1266) driver in the Linux kernel had a vulnerability where a 5-byte stack buffer was used to retrieve the 4-byte BLACKBOX_INFO response from i2c_smbus_read_block_data(). However, i2c_smbus_read_block_data() does not honor caller buffer sizes and can overflow the buffer if the device returns a block length above 5. This vulnerability has been resolved by widening the local buffer to I2C_SMBUS_BLOCK_MAX. The affected product is the Linux kernel, and the vulnerability class is a buffer overflow. The likely operational impact is a potential buffer overflow attack, and defenders should verify the affected scope and severity with the official advisory or CVE record.

Defensive priority

Medium

Recommended defensive actions

• Apply the latest Linux kernel updates
• Ensure the hwmon: (pmbus/adm1266) driver is updated
• Monitor for any potential buffer overflow attacks
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record was published on 2026-07-19T16:17:55.333Z and has not been modified since then. The NVD entry is currently Received. There is limited information available about this vulnerability, and defenders should verify the affected scope and severity with the official advisory or CVE record. The hwmon: (pmbus/adm1266) driver in the Linux kernel had a vulnerability where a 5-byte stack buffer was used to retrieve the 4-byte BLACKBOX_INFO response from i2c_smbus_read_block_data(). However, i2c_smbus_read_block_data() does not honor caller buffer sizes and can overflow the buffer if the device returns a block length above 5. This vulnerability has been resolved by widening the local buffer to I2C_SMBUS_BLOCK_MAX. Linux kernel users and administrators should be aware of this vulnerability and ensure they have the latest kernel updates applied.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.