# CVE-2026-23298: can: ucan: Fix infinite loop from zero-length messages

> A malicious or broken USB CAN device can cause a system hang via an infinite loop in the ucan driver, requiring a kernel patch.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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:** 25 Mar 2026
- **Updated:** 11 May 2026
- **Also known as:** AZL-80658, BELL-CVE-2026-23298, DEBIAN-CVE-2026-23298, GHSA-v7rc-q48q-f2p3, ROOT-OS-DEBIAN-11-CVE-2026-23298, ROOT-OS-DEBIAN-12-CVE-2026-23298, ROOT-OS-DEBIAN-13-CVE-2026-23298, ROOT-OS-UBUNTU-2204-CVE-2026-23298, ROOT-OS-UBUNTU-2404-CVE-2026-23298, UBUNTU-CVE-2026-23298

## What is CVE-2026-23298?

CVE-2026-23298 is a medium-severity denial of service vulnerability in Linux kernel, published on 25 Mar 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: ucan: Fix infinite loop from zero-length messages

If a broken ucan device gets a message with the message length field set
to 0, then the driver will loop for forever in
ucan_read_bulk_callback(), hanging the system.  If the length is 0, just
skip the message and go on to the next one.

This has been fixed in the kvaser_usb driver in the past in commit
0c73772cd2b8 ("can: kvaser_usb: leaf: Fix potential infinite loop in
command parsers"), so there must be some broken devices out there like
this somewhere.

Weakness: CWE-835 (Loop with Unreachable Exit Condition)

## Which versions are affected by CVE-2026-23298?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-23298?

Apply the vendor's patch.

## Is CVE-2026-23298 being exploited?

There is no known exploitation of CVE-2026-23298 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-23298 and fix it if it is affected.

What it is: CVE-2026-23298 is a medium-severity denial of service vulnerability in Linux kernel, published on 25 Mar 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-2026-23298 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2026-23298/ (Markdown: https://insights.sbomify.com/CVE-2026-23298/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-23298
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-23298
- OSV: https://osv.dev/vulnerability/CVE-2026-23298

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-23298/
Summaries are generated and may contain mistakes; the official description above is the record.