# CVE-2025-38273: net: tipc: fix refcount warning in tipc_aead_encrypt

> A use-after-free vulnerability in the Linux kernel TIPC module can cause a refcount warning and potential system instability during network namespace cleanup.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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:** 10 Jul 2025
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2025-38273, DEBIAN-CVE-2025-38273, GHSA-r4r9-4cc8-c2cp, ROOT-OS-DEBIAN-11-CVE-2025-38273, ROOT-OS-DEBIAN-12-CVE-2025-38273, ROOT-OS-UBUNTU-2204-CVE-2025-38273, UBUNTU-CVE-2025-38273

## What is CVE-2025-38273?

CVE-2025-38273 is a high-severity use after free vulnerability in Debian Debian Linux, published on 10 Jul 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: tipc: fix refcount warning in tipc_aead_encrypt

syzbot reported a refcount warning [1] caused by calling get_net() on
a network namespace that is being destroyed (refcount=0). This happens
when a TIPC discovery timer fires during network namespace cleanup.

The recently added get_net() call in commit e279024617134 ("net/tipc:
fix slab-use-after-free Read in tipc_aead_encrypt_done") attempts to
hold a reference to the network namespace. However, if the namespace
is already being destroyed, its refcount might be zero, leading to the
use-after-free warning.

Replace get_net() with maybe_get_net(), which safely checks if the
refcount is non-zero before incrementing it. If the namespace is being
destroyed, return -ENODEV early, after releasing the bearer reference.

[1]: https://lore.kernel.org/all/68342b55.a70a0220.253bc2.0091.GAE@google.com/T/#m12019cf9ae77e1954f666914640efa36d52704a2

## Which versions are affected by CVE-2025-38273?

It affects 2 products.


Products: Debian Debian Linux, Linux kernel.

## How do I fix CVE-2025-38273?

Apply the vendor's patch.

## Is CVE-2025-38273 being exploited?

There is no known exploitation of CVE-2025-38273 in the wild and no public exploit code.

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## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-38273 and fix it if it is affected.

What it is: CVE-2025-38273 is a high-severity use after free vulnerability in Debian Debian Linux, published on 10 Jul 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-2025-38273 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-2025-38273/ (Markdown: https://insights.sbomify.com/CVE-2025-38273/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-38273
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-38273
- OSV: https://osv.dev/vulnerability/CVE-2025-38273

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-38273/
Summaries are generated and may contain mistakes; the official description above is the record.