# CVE-2026-53996: NetBSD hdaudio(4) Driver Privilege Bypass Use-After-Free via HDAUDIO_FGRP_SETCONFIG ioctl

> Unprivileged local attackers can trigger a use-after-free race condition in the NetBSD hdaudio driver, potentially leading to kernel privilege escalation or denial of service.

- **Severity:** High 7.3 (`CVSS:4.0/AV:L/AC:H/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 12 Aug 2026
- **Updated:** 14 Aug 2026
- **Also known as:** GHSA-2q5f-pw9r-2w7m

## What is CVE-2026-53996?

CVE-2026-53996 is a high-severity use after free vulnerability in The NetBSD Foundation NetBSD, published on 12 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

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.

Weakness: CWE-862 (Missing Authorization)

## Which versions are affected by CVE-2026-53996?


## How do I fix CVE-2026-53996?

No fix has been published for CVE-2026-53996 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-53996 being exploited?

There is no known exploitation of CVE-2026-53996 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-53996 and fix it if it is affected.

What it is: CVE-2026-53996 is a high-severity use after free vulnerability in The NetBSD Foundation NetBSD, published on 12 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-53996 in the wild and no public exploit code.

Affected product: The NetBSD Foundation NetBSD. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-53996/ (Markdown: https://insights.sbomify.com/CVE-2026-53996/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-53996
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-53996
- OSV: https://osv.dev/vulnerability/CVE-2026-53996

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-53996/
Summaries are generated and may contain mistakes; the official description above is the record.