# CVE-2025-39827: net: rose: include node references in rose_neigh refcount

> A use-after-free vulnerability in the Linux kernel's ROSE network protocol allows attackers to execute arbitrary code or escalate privileges.

- **Severity:** High 8.8 (`CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **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:** 16 Sep 2025
- **Updated:** 15 Oct 2026
- **Also known as:** AZL-67395, BELL-CVE-2025-39827, DEBIAN-CVE-2025-39827, GHSA-qrx3-r5gv-42g6, ROOT-OS-DEBIAN-11-CVE-2025-39827, ROOT-OS-DEBIAN-12-CVE-2025-39827, ROOT-OS-DEBIAN-13-CVE-2025-39827, ROOT-OS-UBUNTU-2204-CVE-2025-39827, ROOT-OS-UBUNTU-2404-CVE-2025-39827, UBUNTU-CVE-2025-39827

## What is CVE-2025-39827?

CVE-2025-39827 is a high-severity use after free vulnerability in Debian Debian Linux, published on 16 Sep 2025. 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:

net: rose: include node references in rose_neigh refcount

Current implementation maintains two separate reference counting
mechanisms: the 'count' field in struct rose_neigh tracks references from
rose_node structures, while the 'use' field (now refcount_t) tracks
references from rose_sock.

This patch merges these two reference counting systems using 'use' field
for proper reference management. Specifically, this patch adds incrementing
and decrementing of rose_neigh->use when rose_neigh->count is incremented
or decremented.

This patch also modifies rose_rt_free(), rose_rt_device_down() and
rose_clear_route() to properly release references to rose_neigh objects
before freeing a rose_node through rose_remove_node().

These changes ensure rose_neigh structures are properly freed only when
all references, including those from rose_node structures, are released.
As a result, this resolves a slab-use-after-free issue reported by Syzbot.

## Which versions are affected by CVE-2025-39827?

It affects 2 products.


Products: Debian Debian Linux, Linux kernel.

## How do I fix CVE-2025-39827?

Apply the vendor's patch.

## Is CVE-2025-39827 being exploited?

There is no known exploitation of CVE-2025-39827 in the wild and no public exploit code.

## Other vulnerabilities in Debian Debian Linux

- [CVE-2015-3306](https://insights.sbomify.com/CVE-2015-3306/): ProFTPD Improper Access Control (critical 10.0, exploited in the wild)
- [CVE-2025-49113](https://insights.sbomify.com/CVE-2025-49113/): RoundCube Webmail Deserialization of Untrusted Data (critical 9.9, exploited in the wild)
- [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild)
- [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild)
- [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-39827 and fix it if it is affected.

What it is: CVE-2025-39827 is a high-severity use after free vulnerability in Debian Debian Linux, published on 16 Sep 2025. 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-2025-39827 in the wild and no public exploit code.

Affected product: Debian Debian 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-2025-39827/ (Markdown: https://insights.sbomify.com/CVE-2025-39827/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-39827
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-39827
- OSV: https://osv.dev/vulnerability/CVE-2025-39827

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-39827/
Summaries are generated and may contain mistakes; the official description above is the record.