SB20260816225 - Out-of-bounds write in Linux kernel usb



SB20260816225 - Out-of-bounds write in Linux kernel usb

Published: August 16, 2026

Security Bulletin ID SB20260816225
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Physical access
Highest impact Denial of service

Breakdown by Severity

Medium 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Out-of-bounds write (CVE-ID: CVE-2026-74499)

CWE-ID: CWE-787 - Out-of-bounds write

CVSSv4: 5.1 [CVSS:4.0/AV:P/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]


The vulnerability allows an attacker with physical access to cause a denial of service or execute arbitrary code.

The vulnerability exists due to out-of-bounds write in snd_usbmidi_akai_output() when processing MIDI output for a USB device advertising a tiny bulk-OUT endpoint. An attacker with physical access can connect a crafted USB device and trigger a write to the created MIDI device node to cause a denial of service or execute arbitrary code.

The issue is caused by a signed-to-unsigned conversion in the fill-loop bound calculation, making the loop continue writing past the end of the URB transfer buffer.


Remediation

Install update from vendor's website.