# CVE-2026-89486: ipmi: Fix use-after-free of cmd_rcvr in _ipmi_destroy_user()

> A use-after-free in the Linux kernel IPMI driver allows attackers to potentially execute code or escalate privileges due to missing RCU synchronization.

- **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:** 11 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-89486, DEBIAN-CVE-2026-89486, GHSA-6jq9-cvjw-v2h5, UBUNTU-CVE-2026-89486

## What is CVE-2026-89486?

CVE-2026-89486 is a high-severity use after free vulnerability in Linux, published on 11 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:

ipmi: Fix use-after-free of cmd_rcvr in _ipmi_destroy_user()

Commit 9e91f8a6c868 ("ipmi:msghandler: Remove srcu for the
ipmi_interfaces list") dropped the synchronize_rcu() between unlinking
the command receivers from intf->cmd_rcvrs and freeing them, updating
only the comment that explains why the barrier is needed.

The cmd_rcvrs list is still traversed under plain RCU: find_cmd_rcvr()
walks it inside rcu_read_lock(), and handle_ipmb_get_msg_cmd() borrows
rcvr->user from that lookup within the same read-side section. Without
the grace period, _ipmi_destroy_user() can kfree() a cmd_rcvr while a
reader still holds a pointer to it, causing a use-after-free.

The rework only made srcu unnecessary for the interfaces list; the
cmd_rcvrs list still relies on plain RCU. Restore the synchronize_rcu()
before freeing the receivers.

## Which versions are affected by CVE-2026-89486?


## How do I fix CVE-2026-89486?

Apply the vendor's patch.

## Is CVE-2026-89486 being exploited?

There is no known exploitation of CVE-2026-89486 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-89486 and fix it if it is affected.

What it is: CVE-2026-89486 is a high-severity use after free vulnerability in Linux, published on 11 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-2026-89486 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-2026-89486/ (Markdown: https://insights.sbomify.com/CVE-2026-89486/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-89486
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-89486
- OSV: https://osv.dev/vulnerability/CVE-2026-89486

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-89486/
Summaries are generated and may contain mistakes; the official description above is the record.