# CVE-2024-27020: netfilter: nf_tables: Fix potential data-race in __nft_expr_type_get()

> A data race in the Linux kernel netfilter subsystem can lead to undefined behavior during expression type lookups.

- **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:** 1 May 2024
- **Updated:** 15 Oct 2026
- **Also known as:** AZL-42192, BELL-CVE-2024-27020, DEBIAN-CVE-2024-27020, GHSA-rhrr-35q8-4p7f, UBUNTU-CVE-2024-27020

## What is CVE-2024-27020?

CVE-2024-27020 is a high-severity vulnerability in Linux kernel, published on 1 May 2024. 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:

netfilter: nf_tables: Fix potential data-race in __nft_expr_type_get()

nft_unregister_expr() can concurrent with __nft_expr_type_get(),
and there is not any protection when iterate over nf_tables_expressions
list in __nft_expr_type_get(). Therefore, there is potential data-race
of nf_tables_expressions list entry.

Use list_for_each_entry_rcu() to iterate over nf_tables_expressions
list in __nft_expr_type_get(), and use rcu_read_lock() in the caller
nft_expr_type_get() to protect the entire type query process.

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

## Which versions are affected by CVE-2024-27020?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2024-27020?

Apply the vendor's patch.

## Is CVE-2024-27020 being exploited?

There is no known exploitation of CVE-2024-27020 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-2024-27020 and fix it if it is affected.

What it is: CVE-2024-27020 is a high-severity vulnerability in Linux kernel, published on 1 May 2024. 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-2024-27020 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-2024-27020/ (Markdown: https://insights.sbomify.com/CVE-2024-27020/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-27020
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-27020
- OSV: https://osv.dev/vulnerability/CVE-2024-27020

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-27020/
Summaries are generated and may contain mistakes; the official description above is the record.