# CVE-2025-71182: can: j1939: make j1939_session_activate() fail if device is no longer registered

> A race condition in the Linux kernel CAN J1939 protocol allows a denial of service by preventing network device unregistration.

- **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:** 31 Jan 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2025-71182, DEBIAN-CVE-2025-71182, GHSA-266h-p8pw-28f4, ROOT-OS-DEBIAN-11-CVE-2025-71182, ROOT-OS-DEBIAN-12-CVE-2025-71182, ROOT-OS-DEBIAN-13-CVE-2025-71182, ROOT-OS-UBUNTU-2204-CVE-2025-71182, ROOT-OS-UBUNTU-2404-CVE-2025-71182, UBUNTU-CVE-2025-71182

## What is CVE-2025-71182?

CVE-2025-71182 is a medium-severity vulnerability in Linux kernel, published on 31 Jan 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: j1939: make j1939_session_activate() fail if device is no longer registered

syzbot is still reporting

  unregister_netdevice: waiting for vcan0 to become free. Usage count = 2

even after commit 93a27b5891b8 ("can: j1939: add missing calls in
NETDEV_UNREGISTER notification handler") was added. A debug printk() patch
found that j1939_session_activate() can succeed even after
j1939_cancel_active_session() from j1939_netdev_notify(NETDEV_UNREGISTER)
has completed.

Since j1939_cancel_active_session() is processed with the session list lock
held, checking ndev->reg_state in j1939_session_activate() with the session
list lock held can reliably close the race window.

Weakness: CWE-362 (Concurrent Execution using Shared Resource with Improper Synchronization)

## Which versions are affected by CVE-2025-71182?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2025-71182?

Apply the vendor's patch.

## Is CVE-2025-71182 being exploited?

There is no known exploitation of CVE-2025-71182 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-2025-71182 and fix it if it is affected.

What it is: CVE-2025-71182 is a medium-severity vulnerability in Linux kernel, published on 31 Jan 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-2025-71182 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-2025-71182/ (Markdown: https://insights.sbomify.com/CVE-2025-71182/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-71182
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-71182
- OSV: https://osv.dev/vulnerability/CVE-2025-71182

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-71182/
Summaries are generated and may contain mistakes; the official description above is the record.