# CVE-2026-68201: ALSA: timer: drain a slave's callback before its master detaches it

> A use-after-free in the Linux kernel ALSA timer allows local attackers to execute arbitrary code or escalate privileges when a master timer instance is closed while a slave callback is running.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **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:** Yes
- **Published:** 10 Aug 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-68201, DEBIAN-CVE-2026-68201, GHSA-793q-4mv8-rvwh, UBUNTU-CVE-2026-68201

## What is CVE-2026-68201?

CVE-2026-68201 is a high-severity use after free vulnerability in Linux, published on 10 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

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

ALSA: timer: drain a slave's callback before its master detaches it

snd_timer_close_locked() drains the closing instance's own in-flight
callback (IFLG_CALLBACK) before freeing it, but not its slaves'. When a
master instance is closed, remove_slave_links() clears each slave's
->timer; the slave's own close then reads timer == NULL and takes the
branch that skips the drain entirely (snd_timer_stop_slave() also no-ops
on a NULL timer). So a slave whose callback is still running when the
master is closed is freed underneath the live callback, leading to
use-after-free.

Drain the slaves too before remove_slave_links() severs them.
snd_timer_stop() has already taken this instance off the active list, so
no new slave callback can be queued. Take the slaves off the ack list so
a pending one can't fire either, then wait for any that is already in
flight.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2026-68201?


## How do I fix CVE-2026-68201?

Apply the vendor's patch.

## Is CVE-2026-68201 being exploited?

There is no known exploitation of CVE-2026-68201 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-68201 and fix it if it is affected.

What it is: CVE-2026-68201 is a high-severity use after free vulnerability in Linux, published on 10 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-2026-68201 in the wild and no public exploit code.

Affected product: Linux. 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-2026-68201/ (Markdown: https://insights.sbomify.com/CVE-2026-68201/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-68201
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-68201
- OSV: https://osv.dev/vulnerability/CVE-2026-68201

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-68201/
Summaries are generated and may contain mistakes; the official description above is the record.