---
id: CVE-2026-90386
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  i3c: dw: avoid shift-out-of-bounds when DAA assigns no devices

  On an empty bus ENTDAA assigns nothing, so cmd->rx_len (the count
  of addresses left unassigned) equals m…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  i3c: dw: avoid shift-out-of-bounds when DAA assigns no devices

  On an empty bus ENTDAA assigns nothing, so cmd->rx_len (the count
  of addresses left unassigned) equals m…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 1dd728f5d4d4b8b53196c1e0fcf86bbaaee39cef <
    5650b013e6bfc14c8b30be727f4a715b01860a08
  - >-
    Linux >= 1dd728f5d4d4b8b53196c1e0fcf86bbaaee39cef <
    63110ccc434e10d9e9d2c7d82ebfa8a6f9cedd94
  - >-
    Linux >= 1dd728f5d4d4b8b53196c1e0fcf86bbaaee39cef <
    3a1c35739efb69e8ec2a868113a0471a01bb8f29
  - >-
    Linux >= 1dd728f5d4d4b8b53196c1e0fcf86bbaaee39cef <
    111f559e5b6461f5f6977275716e6c5d1eb7ea27
  - >-
    Linux >= 1dd728f5d4d4b8b53196c1e0fcf86bbaaee39cef <
    754533e6169d1f10bdef7a6ba9bd7740b524e1d4
  - >-
    Linux >= 1dd728f5d4d4b8b53196c1e0fcf86bbaaee39cef <
    9eaac0cb4ca94e2e32c53c156ae5b813ba7ef90c
  - >-
    Linux >= 1dd728f5d4d4b8b53196c1e0fcf86bbaaee39cef <
    618dd640ded6b94bbdb79c798a901ec564797033
  - >-
    Linux >= 1dd728f5d4d4b8b53196c1e0fcf86bbaaee39cef <
    038cf48b3170af26a70bf2dee4f8c3ac910f5176
  - Linux 5.0
published: '2026-09-17'
updated: '2026-09-17'
sourceUpdated: '2026-09-17T17:17:37.993'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-90386'
references:
  - url: 'https://git.kernel.org/stable/c/038cf48b3170af26a70bf2dee4f8c3ac910f5176'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/111f559e5b6461f5f6977275716e6c5d1eb7ea27'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/3a1c35739efb69e8ec2a868113a0471a01bb8f29'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/5650b013e6bfc14c8b30be727f4a715b01860a08'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/618dd640ded6b94bbdb79c798a901ec564797033'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/63110ccc434e10d9e9d2c7d82ebfa8a6f9cedd94'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/754533e6169d1f10bdef7a6ba9bd7740b524e1d4'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/9eaac0cb4ca94e2e32c53c156ae5b813ba7ef90c'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-17T16:21:47.806Z'
epss: 0.0022
epssPercentile: 0.11039
---

## Overview

In the Linux kernel, the following vulnerability has been resolved:

i3c: dw: avoid shift-out-of-bounds when DAA assigns no devices

On an empty bus ENTDAA assigns nothing, so cmd->rx_len (the count
of addresses left unassigned) equals master->maxdevs.

The GENMASK() index master->maxdevs - cmd->rx_len - 1 then becomes -1,
which trips up UBSAN. This happens every time on boot on a Gigabyte/AMD
server:

    UBSAN: shift-out-of-bounds in drivers/i3c/master/dw-i3c-master.c:905:12
    shift exponent 64 is too large for 64-bit type 'long unsigned int'
    CPU: 7 UID: 0 PID: 963 Comm: (udev-worker) Not tainted 7.0.11-200.fc44.x86_64 #1 PREEMPT(lazy)
    Hardware name: Giga Computing E163-Z34-AAH1-000/MZ33-DC1-000, BIOS R32_F45 04/01/2026
    Call Trace:
     <TASK>
     dump_stack_lvl+0x5d/0x80
     ubsan_epilogue+0x5/0x2b
     __ubsan_handle_shift_out_of_bounds.cold+0xd7/0x1ab
     dw_i3c_master_daa.cold+0x1b/0x96 [dw_i3c_master]
     i3c_master_do_daa_ext.part.0+0x3e/0xf0 [i3c]

Skip the mask when no new device was assigned.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.