Junglewise Threat Intelligence

CVE-2026-63958: Linux Kernel out-of-bounds access in USB UCSI driver

CVE-2026-63958 · Severity: info · CVSS 0 · Published 2026-07-19

Technologies: Linux Kernel. Vendors: Linux.

Executive brief

A vulnerability in the Linux kernel's USB Type-C implementation could allow a faulty or malicious hardware component to cause a system crash or execute unintended operations. This occurs when the system receives a notification from a USB controller but fails to verify if the connector ID provided is valid before using it. This issue primarily affects systems using specific USB-C hardware controllers or firmware.

Technical details

An out-of-bounds array index vulnerability exists in the ucsi_connector_change() function within drivers/usb/typec/ucsi/ucsi.c. The connector number provided in a UCSI CCI notification is a 7-bit field supplied by the Platform Policy Manager (PPM). The driver uses this value to index the ucsi->connector[] array without verifying it against the maximum number of connectors reported during initialization. A malicious or buggy PPM (such as EC firmware or an I2C-attached UCSI controller) can provide an invalid index, causing the kernel to call schedule_work() on memory past the end of the array. This has been patched by adding bounds checking to reject connector numbers that are zero or exceed the reported capacity.

Affected products

  • Linux Linux Kernel 6.1.176, 6.6.143, 6.12.93, 6.18.35, 7.0.12

Timeline

  • 2026-05-13: patched: Initial patch authored by Greg Kroah-Hartman
  • 2026-07-19: disclosed: CVE published to the NVD dataset

References

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