# CVE-2026-23058: can: ems_usb: ems_usb_read_bulk_callback(): fix URB memory leak

> A memory leak in the Linux kernel EMS USB CAN driver allows local attackers to exhaust system memory, causing denial of service.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 4 Feb 2026
- **Updated:** 11 May 2026
- **Also known as:** AZL-77196, BELL-CVE-2026-23058, DEBIAN-CVE-2026-23058, GHSA-7g6w-2p3x-pf3p, ROOT-OS-DEBIAN-11-CVE-2026-23058, ROOT-OS-DEBIAN-12-CVE-2026-23058, ROOT-OS-DEBIAN-13-CVE-2026-23058, ROOT-OS-UBUNTU-2204-CVE-2026-23058, ROOT-OS-UBUNTU-2404-CVE-2026-23058, UBUNTU-CVE-2026-23058

## What is CVE-2026-23058?

CVE-2026-23058 is a memory corruption vulnerability in Linux, published on 4 Feb 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: ems_usb: ems_usb_read_bulk_callback(): fix URB memory leak

Fix similar memory leak as in commit 7352e1d5932a ("can: gs_usb:
gs_usb_receive_bulk_callback(): fix URB memory leak").

In ems_usb_open(), the URBs for USB-in transfers are allocated, added to
the dev->rx_submitted anchor and submitted. In the complete callback
ems_usb_read_bulk_callback(), the URBs are processed and resubmitted. In
ems_usb_close() the URBs are freed by calling
usb_kill_anchored_urbs(&dev->rx_submitted).

However, this does not take into account that the USB framework unanchors
the URB before the complete function is called. This means that once an
in-URB has been completed, it is no longer anchored and is ultimately not
released in ems_usb_close().

Fix the memory leak by anchoring the URB in the
ems_usb_read_bulk_callback() to the dev->rx_submitted anchor.

## Which versions are affected by CVE-2026-23058?


## How do I fix CVE-2026-23058?

Apply the vendor's patch.

## Is CVE-2026-23058 being exploited?

There is no known exploitation of CVE-2026-23058 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-23058 and fix it if it is affected.

What it is: CVE-2026-23058 is a memory corruption vulnerability in Linux, published on 4 Feb 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-2026-23058 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-2026-23058/ (Markdown: https://insights.sbomify.com/CVE-2026-23058/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-23058
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-23058
- OSV: https://osv.dev/vulnerability/CVE-2026-23058

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-23058/
Summaries are generated and may contain mistakes; the official description above is the record.