Executive brief
The Linux kernel's i3c (Improved Inter-Integrated Circuit) bus master driver incorrectly identifies the controller itself as a duplicate target device during bus enumeration. This logic error could cause the bus discovery process to malfunction, potentially preventing legitimate i3c devices from being properly detected and initialized on systems using i3c interfaces (e.g., certain server management and IoT platforms).
Technical details
The vulnerability is a logic error in the i3c_master_search_i3c_dev_duplicate() function within drivers/i3c/master.c. This function searches the i3c bus for duplicate devices by comparing product IDs (PIDs), but the search loop did not exclude the master controller's own device descriptor (master->this), allowing the controller to match against itself and be incorrectly flagged as a duplicate target. Since the master controller is not a target device, this causes incorrect duplicate detection. The fix adds an explicit check to exclude master->this from the duplicate matching logic. No authentication, network access, or user interaction is required; the bug affects the kernel's internal device enumeration. The impact is functional incorrect behavior during i3c bus initialization rather than a security vulnerability, hence the "info" severity classification.
Affected products
- Linux Linux kernel affected versions include i3c master driver from initial commit (3a379bbcea0a) through patches applied September 2026
Timeline
- 2026-09-17: disclosed: CVE-2026-93199 published
- 2026-08-07: patched: Upstream fix committed by Adrian Hunter
- 2026-09-14: patched: Backport released in stable kernel