# CVE-2026-72454: i3c: mipi-i3c-hci: Fix race in i3c_hci_addr_to_dev()

> A race condition in the Linux kernel I3C HCI driver allows concurrent list modification, potentially causing use-after-free crashes or code execution.

- **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:** 15 Oct 2026
- **Also known as:** BELL-CVE-2026-72454, DEBIAN-CVE-2026-72454, GHSA-48cg-fm56-jr4v, UBUNTU-CVE-2026-72454

## What is CVE-2026-72454?

CVE-2026-72454 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:

i3c: mipi-i3c-hci: Fix race in i3c_hci_addr_to_dev()

i3c_hci_addr_to_dev() walks bus->devs.i3c, which is protected by
bus.lock (rwsem).  However, it is invoked from the MIPI I3C HCI IRQ
handler, which cannot take bus.lock.  This allows concurrent device
addition/removal in the I3C core to modify the list while it is being
traversed, potentially leading to use-after-free or crashes.

Remove the dependency on the bus device list and introduce a dedicated
lookup table.  Add an ibi_devs[] array indexed by DAT entry, maintained
under hci->lock.  Update the array when IBIs are enabled or disabled,
so that it always reflects the set of devices allowed to generate IBIs.
Also update when IBIs are freed, to cover the corner case when an IBI is
freed without first being disabled (e.g. oldedev in
i3c_master_add_i3c_dev_locked()).

Move i3c_hci_addr_to_dev() into core.c, reimplement it using the new
array, and add a lockdep assertion to enforce that hci->lock is held
by callers.

Demote a message in PIO and DMA IBI handling, from an error to a debug
message, because there is a race window when the condition can arise
normally.

## Which versions are affected by CVE-2026-72454?


## How do I fix CVE-2026-72454?

Apply the vendor's patch.

## Is CVE-2026-72454 being exploited?

There is no known exploitation of CVE-2026-72454 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-72454 and fix it if it is affected.

What it is: CVE-2026-72454 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-2026-72454 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-2026-72454/ (Markdown: https://insights.sbomify.com/CVE-2026-72454/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-72454
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-72454
- OSV: https://osv.dev/vulnerability/CVE-2026-72454

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-72454/
Summaries are generated and may contain mistakes; the official description above is the record.