Bug 2502319 (CVE-2026-63958)

Summary: CVE-2026-63958 kernel: usb: typec: ucsi: validate connector number in ucsi_connector_change()
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
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Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's USB Type-C subsystem. This vulnerability allows a malicious or buggy Power Delivery Microcontroller (PPM), such as embedded controller (EC) firmware or an I2C-attached Universal Serial Bus (USB) Type-C Connector System Interface (UCSI) controller, to provide an invalid connector number. This invalid number is then used to access memory beyond the intended array boundaries, which can lead to a system crash. The primary consequence is a denial of service, making the system unavailable.
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Description OSIDB Bzimport 2026-07-19 16:01:41 UTC 
In the Linux kernel, the following vulnerability has been resolved:

usb: typec: ucsi: validate connector number in ucsi_connector_change()

The connector number in a UCSI CCI notification is a 7-bit field
supplied by the PPM.  ucsi_connector_change() uses it to index the
ucsi->connector[] array without checking it against the number of
connectors the PPM reported at init time, so a buggy or malicious PPM
(EC firmware, or an I2C-attached UCSI controller on the ccg / stm32g0 /
glink transports) can drive schedule_work() on memory past the end of
the array.

Reject connector numbers that are zero or exceed cap.num_connectors
before dereferencing the array.
Comment 1 Keith Grant 2026-07-21 22:47:19 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026071956-CVE-2026-63958-c77b@gregkh/T