CVE-2026-64085 Linux CVE debrief

Who should care

Linux kernel users and administrators should be aware of this vulnerability and take necessary actions to protect their systems. They should verify and apply patches for the hwmon: (pmbus/adm1266) component and monitor system logs for suspicious activity. Affected operator, platform, vulnerability-management, and security-team impact should be considered.

Technical summary

The Linux kernel vulnerability, CVE-2026-64085, is related to the hwmon: (pmbus/adm1266) component. The vulnerability arises from the adm1266_pmbus_block_xfer() function, which copies device-supplied block payload into the caller-provided buffer using the device-supplied length. The helper does not know how large the data_r buffer is and trusts the device to return at most one record's worth of bytes. Contain the fix in the caller without changing the helper signature: read each record into a 255-byte local bounce buffer that matches the helper's maximum output, validate the returned length, and only then copy exactly ADM1266_BLACKBOX_SIZE bytes into the dev_mem slot.

Defensive priority

High

Recommended defensive actions

• Update Linux kernel to the latest version
• Verify and apply patches for the hwmon: (pmbus/adm1266) component
• Monitor system logs for suspicious activity
• 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 2026-07-19T16:17:49.173Z and has not been modified since then. The NVD entry is currently Received. The Linux kernel vulnerability, CVE-2026-64085, is related to the hwmon: (pmbus/adm1266) component. The vulnerability arises from the adm1266_pmbus_block_xfer() function, which copies device-supplied block payload into the caller-provided buffer using the device-supplied length. The helper does not know how large the data_r buffer is and trusts the device to return at most one record's worth of bytes. Contain the fix in the caller without changing the helper signature: read each record into a 255-byte local bounce buffer that matches the helper's maximum output, validate the returned length, and only then copy exactly ADM1266_BLACKBOX_SIZE bytes into the dev_mem slot. Linux kernel users and administrators should verify and apply patches for the hwmon: (pmbus/adm1266) component and monitor system logs for suspicious activity.

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.