# CVE-2026-72042: ipmi: Fix user refcount underflow in event delivery

> A use-after-free vulnerability in the Linux kernel IPMI driver allows attackers to cause denial of service or potentially execute code via event delivery failures.

- **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:** 15 Aug 2026
- **Updated:** 17 Aug 2026
- **Also known as:** AZL-96366, BELL-CVE-2026-72042, DEBIAN-CVE-2026-72042, GHSA-vqpc-pm2x-2835, UBUNTU-CVE-2026-72042

## What is CVE-2026-72042?

CVE-2026-72042 is a high-severity use after free vulnerability in Linux, published on 15 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:

ipmi: Fix user refcount underflow in event delivery

ipmi_alloc_recv_msg(user) takes the temporary user reference owned by the
receive message, and ipmi_free_recv_msg() drops it again. If event delivery
fails after allocating receive messages for earlier users,
handle_read_event_rsp() rolls those messages back with
ipmi_free_recv_msg().

That rollback path still drops user->refcount explicitly after freeing each
message. The extra put can free a user that remains linked on intf->users,
so later event delivery may dereference a freed user or trip refcount_t's
addition-on-zero warning when ipmi_alloc_recv_msg() tries to acquire
another reference.

Remove the stale explicit put and the now-dead user assignment. Keep the
list_del() and ipmi_free_recv_msg() calls; they are the required rollback
operations.

## Which versions are affected by CVE-2026-72042?


## How do I fix CVE-2026-72042?

Apply the vendor's patch.

## Is CVE-2026-72042 being exploited?

There is no known exploitation of CVE-2026-72042 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-72042 and fix it if it is affected.

What it is: CVE-2026-72042 is a high-severity use after free vulnerability in Linux, published on 15 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-2026-72042 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-2026-72042/ (Markdown: https://insights.sbomify.com/CVE-2026-72042/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-72042
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-72042
- OSV: https://osv.dev/vulnerability/CVE-2026-72042

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-72042/
Summaries are generated and may contain mistakes; the official description above is the record.