CVE-2026-63959 Linux CVE debrief

Who should care

Linux kernel maintainers, Linux distribution vendors, and users of Linux-based systems should be aware of this vulnerability and take steps to mitigate it. Affected operators and platforms should review the vulnerability and implement compensating controls if necessary.

Technical summary

The Linux kernel's USB type-c TC PM TCP CI Maxim driver does not properly validate the header NDO against the RX_BYTE_CNT. This can cause the kernel to read from uninitialized stack memory when a malicious port transmits a CRC-valid frame with a header advertising more data objects than its body carries. The vulnerability has been resolved in the Linux kernel. Affected Linux kernel maintainers, Linux distribution vendors, and users of Linux-based systems should be aware of this vulnerability and take steps to mitigate it. The vulnerability affects Linux kernel versions and requires verification and updates to ensure the fix is applied. Monitoring system logs for potential exploitation attempts and reviewing compensating controls for exposed systems are recommended while remediation is scheduled and verified.

Defensive priority

Medium

Recommended defensive actions

• Apply the official patch from the Linux kernel maintainers
• Verify and update Linux kernel versions to ensure the fix is applied
• Monitor system logs for potential exploitation attempts
• 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 2026-07-19T16:17:14.780Z and has not been modified since then. The NVD entry is currently Received. There is limited information available about the vulnerability, and defenders should verify the affected scope and severity with the Linux kernel maintainers. The vulnerability affects the Linux kernel's USB type-c TC PM TCP CI Maxim driver.

Official resources