# CVE-2026-72373: afs: Fix missing NULL pointer check in afs_break_some_callbacks()

> A missing NULL pointer check in the Linux kernel AFS module can cause a system crash when an unknown volume is specified.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 15 Aug 2026
- **Updated:** 16 Oct 2026
- **Also known as:** BELL-CVE-2026-72373, DEBIAN-CVE-2026-72373, GHSA-4h6c-mrxr-5r6x, UBUNTU-CVE-2026-72373

## What is CVE-2026-72373?

CVE-2026-72373 is a high-severity vulnerability in Linux, published on 15 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

afs: Fix missing NULL pointer check in afs_break_some_callbacks()

Fix afs_break_some_callbacks() to check to see if afs_lookup_volume_rcu()
returned NULL (e.g. the specified volume is unknown).

## Which versions are affected by CVE-2026-72373?


## How do I fix CVE-2026-72373?

Apply the vendor's patch.

## Is CVE-2026-72373 being exploited?

There is no known exploitation of CVE-2026-72373 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-72373 and fix it if it is affected.

What it is: CVE-2026-72373 is a high-severity vulnerability in Linux, published on 15 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-72373 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-2026-72373/ (Markdown: https://insights.sbomify.com/CVE-2026-72373/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-72373
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-72373
- OSV: https://osv.dev/vulnerability/CVE-2026-72373

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-72373/
Summaries are generated and may contain mistakes; the official description above is the record.