---
id: CVE-2026-53996
title: >-
  NetBSD's hdaudio(4) driver in sys/dev/hdaudio/hdaudio.c contains a missing
  access control vulnerability that allows unprivileged local attackers to
  invoke the HDAUDIO_FGRP_SETCONFIG ioctl without elevated permissions by
  exploiting the ab…
summary: >-
  NetBSD's hdaudio(4) driver in sys/dev/hdaudio/hdaudio.c contains a missing
  access control vulnerability that allows unprivileged local attackers to
  invoke the HDAUDIO_FGRP_SETCONFIG ioctl without elevated permissions by
  exploiting the ab…
severity: high
cvss: 7
cvssVector: 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-862
published: '2026-08-12'
updated: '2026-09-24'
sourceUpdated: '2026-09-24T20:30:35.900'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-53996'
references:
  - url: 'https://cvsweb.NetBSD.org/bsdweb.cgi/src/sys/dev/hdaudio/hdaudio.c'
    label: disclosure@vulncheck.com
  - url: 'https://gist.github.com/n4sm/c9683ca728ecfada6c726f2a5afb50ed'
    label: disclosure@vulncheck.com
  - url: 'https://gnats.netbsd.org/60492'
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/netbsd-hdaudio-4-driver-privilege-bypass-use-after-free-via-hdaudio-fgrp-setconfig-ioctl
    label: disclosure@vulncheck.com
tags:
  - nvd
epss: 0.00128
epssPercentile: 0.02056
ingestedAt: '2026-09-24T20:51:40.198Z'
---

## Overview

NetBSD's hdaudio(4) driver in sys/dev/hdaudio/hdaudio.c contains a missing access control vulnerability that allows unprivileged local attackers to invoke the HDAUDIO_FGRP_SETCONFIG ioctl without elevated permissions by exploiting the absence of an access check on /dev/hdaudioN device nodes. Attackers can repeatedly issue HDAUDIO_FGRP_SETCONFIG from one thread while keeping DMA and IRQs live from a second thread to trigger a use-after-free race condition in hdafg_detach() between stream_stop() and stream_disestablish(), where a latched DMA interrupt dereferences a freed callback pointer, resulting in outcomes ranging from audio-subsystem denial of service and kernel panic to potential local kernel privilege escalation.

## Remediation

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