# CVE-2026-98086: ALSA: ump: do not touch legacy_rmidi before it exists

> A null pointer dereference in the Linux kernel ALSA UMP driver allows local attackers to cause a system crash via crafted UMP packets.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 25 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-104622, BELL-CVE-2026-98086, DEBIAN-CVE-2026-98086, GHSA-54q5-26wc-pgp6, UBUNTU-CVE-2026-98086

## What is CVE-2026-98086?

CVE-2026-98086 is a vulnerability in Linux, published on 25 Sep 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: ump: do not touch legacy_rmidi before it exists

snd_ump_parse_endpoint() sets ump->parsed on every exit, including
error, before the caller attaches the legacy rawmidi device.
ump_handle_ep_name_msg() then treats parsed as "legacy_rmidi is live"
and calls ump_legacy_set_rawmidi_name(), which snprintf()s into
ump->legacy_rmidi->name. If a UMP packet arrives in that window
(IRQ path from snd_ump_receive), legacy_rmidi is still NULL
(KASAN null-ptr-deref in snprintf).

Guard the legacy helpers. parsed only means endpoint info was
parsed, not that legacy_rmidi exists.

## Which versions are affected by CVE-2026-98086?


## How do I fix CVE-2026-98086?

Apply the vendor's patch.

## Is CVE-2026-98086 being exploited?

There is no known exploitation of CVE-2026-98086 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98086 and fix it if it is affected.

What it is: CVE-2026-98086 is a vulnerability in Linux, published on 25 Sep 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-2026-98086 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-2026-98086/ (Markdown: https://insights.sbomify.com/CVE-2026-98086/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98086
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98086
- OSV: https://osv.dev/vulnerability/CVE-2026-98086

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98086/
Summaries are generated and may contain mistakes; the official description above is the record.