Auth bypass in The NetBSD Foundation
CVE-2026-53996
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.
Vulnerability class: Broken Access Control
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.0 (High). Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.001 (2.1th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 2nd percentile — 2.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.001 · newest: 0.001 · change: +0.000
Affected products
- The NetBSD Foundation — versions 0
Weakness classification (CWE)
References
- gist.github.com/n4sm/c9683ca728ecfada6c726f2a5afb50ed (technical-description)
- gnats.netbsd.org/60492 (issue-tracking)
- cvsweb.NetBSD.org/bsdweb.cgi/src/sys/dev/hdaudio/hdaudio.c (patch)
- www.vulncheck.com/advisories/netbsd-hdaudio-4-driver-privilege-bypass-use-after… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-53996?
- CVE-2026-53996 is a high-severity vulnerability in The NetBSD Foundation, classified under Missing Authorization. CVSS score: 7.0/10. Published 2026-08-12.
- How severe is CVE-2026-53996?
- High severity. CVSS v3 base score is 7.0 out of 10.