# CVE-2026-72120: can: bcm: add missing rcu list annotations and operations

> A race condition in the Linux kernel CAN BCM module due to missing RCU list operations can lead to system instability or crashes.

- **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:** 16 Oct 2026
- **Also known as:** BELL-CVE-2026-72120, DEBIAN-CVE-2026-72120, GHSA-v4mr-5hv5-p6wp, UBUNTU-CVE-2026-72120

## What is CVE-2026-72120?

CVE-2026-72120 is a high-severity 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:

can: bcm: add missing rcu list annotations and operations

sashiko-bot remarked the missing use of list_add_rcu() in
bcm_[rx|tx]_setup() to have a proper initialized bcm_op structure
when bcm_proc_show() traverses the bcm_op's under rcu_read_lock().

To cover all initial settings of the bcm_op's the list_add_rcu() calls
are moved to the end of the setup code.

While at it, also fix the mirroring removal side: bcm_release() called
bcm_remove_op() - which frees the op via call_rcu() - on ops that were
still linked in bo->tx_ops/bo->rx_ops, without list_del_rcu() first.
Unlink each op with list_del_rcu() before handing it to bcm_remove_op(),
matching the existing pattern in bcm_delete_tx_op()/bcm_delete_rx_op().

## Which versions are affected by CVE-2026-72120?


## How do I fix CVE-2026-72120?

Apply the vendor's patch.

## Is CVE-2026-72120 being exploited?

There is no known exploitation of CVE-2026-72120 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-72120 and fix it if it is affected.

What it is: CVE-2026-72120 is a high-severity 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-2026-72120 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-2026-72120/ (Markdown: https://insights.sbomify.com/CVE-2026-72120/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-72120
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-72120
- OSV: https://osv.dev/vulnerability/CVE-2026-72120

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-72120/
Summaries are generated and may contain mistakes; the official description above is the record.