# CVE-2026-72047: ieee802154: ca8210: fix pointer truncation in kfifo on 64-bit


- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 15 Aug 2026
- **Updated:** 17 Aug 2026
- **Also known as:** BELL-CVE-2026-72047, DEBIAN-CVE-2026-72047, GHSA-r4v9-gf4r-42ww, UBUNTU-CVE-2026-72047

## What is CVE-2026-72047?

CVE-2026-72047 is a vulnerability in Linux, published on 15 Aug 2026. 

### Official description

In the Linux kernel, the following vulnerability has been resolved:

ieee802154: ca8210: fix pointer truncation in kfifo on 64-bit

ca8210_test_int_driver_write() and ca8210_test_int_user_read() exchange
a kmalloc'd buffer pointer through a struct kfifo, but pass a literal
'4' as the byte count to kfifo_in()/kfifo_out().

This is correct on 32-bit (pointer = 4 bytes), but on 64-bit only the
low 4 bytes of the 8-byte pointer are written into the FIFO. The reader
then reads back 4 bytes into an 8-byte local pointer variable, leaving
the upper 4 bytes uninitialized stack data. The first dereference of
the reconstructed pointer (fifo_buffer[1]) accesses an arbitrary kernel
address and generally results in an oops.

Use sizeof(fifo_buffer) so the byte count matches pointer width on every
architecture.

The driver has no architecture restriction in Kconfig, so any 64-bit
build with CONFIG_IEEE802154_CA8210_DEBUGFS=y is exposed. Issue has
been latent since the driver was added in 2017 because it is most
commonly deployed on 32-bit MCUs.

Found via a custom Coccinelle semantic patch hunting for short-byte
kfifo I/O on byte-mode kfifos used to shuttle pointers.

## Which versions are affected by CVE-2026-72047?


## How do I fix CVE-2026-72047?

Upgrade to a fixed version.

## Is CVE-2026-72047 being exploited?

There is no known exploitation of CVE-2026-72047 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-72047 and fix it if it is affected.

What it is: CVE-2026-72047 is a vulnerability in Linux, published on 15 Aug 2026. 
Exploitation: There is no known exploitation of CVE-2026-72047 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-2026-72047/ (Markdown: https://insights.sbomify.com/CVE-2026-72047/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-72047
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-72047
- OSV: https://osv.dev/vulnerability/CVE-2026-72047

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-72047/
Summaries are generated and may contain mistakes; the official description above is the record.