# CVE-2023-4147: Kernel: netfilter: nf_tables_newrule when adding a rule with nfta_rule_chain_id leads to use-after-free

> A local attacker can exploit a use-after-free in the Linux kernel's netfilter subsystem to crash the system or escalate privileges.

- **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:** 7 Aug 2023
- **Updated:** 25 Feb 2026
- **Also known as:** AZL-27897, CVE-2023-3995, DEBIAN-CVE-2023-4147, GHSA-pcv9-72q8-27vc, UBUNTU-CVE-2023-4147

## What is CVE-2023-4147?

CVE-2023-4147 is a high-severity use after free vulnerability in Debian Debian Linux, published on 7 Aug 2023. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A use-after-free flaw was found in the Linux kernel’s Netfilter functionality when adding a rule with NFTA_RULE_CHAIN_ID. This flaw allows a local user to crash or escalate their privileges on the system.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2023-4147?

It affects 8 products.


Products: Debian Debian Linux, Fedoraproject Fedora, Linux kernel, Redhat Enterprise Linux, Redhat Enterprise Linux Eus, Redhat Enterprise Linux for Real Time, Redhat Enterprise Linux for Real Time for Nfv, Redhat Enterprise Linux Server Aus.

## How do I fix CVE-2023-4147?

Apply the vendor's patch.

## Is CVE-2023-4147 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-4147 exists.

Public exploit code:

- PoC educativo del exploit CVE-2023-4147 (Linux kernel Netfilter UAF) — solo para entornos autorizados (github_poc): https://github.com/murdok1982/Exploit-en-Python-para-CVE-2023-4147

## 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-2023-4147 and fix it if it is affected.

What it is: CVE-2023-4147 is a high-severity use after free vulnerability in Debian Debian Linux, published on 7 Aug 2023. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-4147 exists.

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-2023-4147/ (Markdown: https://insights.sbomify.com/CVE-2023-4147/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-4147
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-4147
- OSV: https://osv.dev/vulnerability/CVE-2023-4147

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-4147/
Summaries are generated and may contain mistakes; the official description above is the record.