# CVE-2024-39503: netfilter: ipset: Fix race between namespace cleanup and gc in the list:set type

> A race condition in the Linux kernel ipset module allows local attackers to trigger a use-after-free, potentially leading to code execution or privilege escalation.

- **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:** 12 Jul 2024
- **Updated:** 15 Oct 2026
- **Also known as:** BELL-CVE-2024-39503, DEBIAN-CVE-2024-39503, GHSA-r75c-r77g-h7h2, UBUNTU-CVE-2024-39503

## What is CVE-2024-39503?

CVE-2024-39503 is a high-severity use after free vulnerability in Linux kernel, published on 12 Jul 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: ipset: Fix race between namespace cleanup and gc in the list:set type

Lion Ackermann reported that there is a race condition between namespace cleanup
in ipset and the garbage collection of the list:set type. The namespace
cleanup can destroy the list:set type of sets while the gc of the set type is
waiting to run in rcu cleanup. The latter uses data from the destroyed set which
thus leads use after free. The patch contains the following parts:

- When destroying all sets, first remove the garbage collectors, then wait
  if needed and then destroy the sets.
- Fix the badly ordered "wait then remove gc" for the destroy a single set
  case.
- Fix the missing rcu locking in the list:set type in the userspace test
  case.
- Use proper RCU list handlings in the list:set type.

The patch depends on c1193d9bbbd3 (netfilter: ipset: Add list flush to cancel_gc).

Weakness: CWE-416 (Use After Free), CWE-362 (Concurrent Execution using Shared Resource with Improper Synchronization)

## Which versions are affected by CVE-2024-39503?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2024-39503?

Apply the vendor's patch.

## Is CVE-2024-39503 being exploited?

There is no known exploitation of CVE-2024-39503 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-2024-39503 and fix it if it is affected.

What it is: CVE-2024-39503 is a high-severity use after free vulnerability in Linux kernel, published on 12 Jul 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-2024-39503 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-2024-39503/ (Markdown: https://insights.sbomify.com/CVE-2024-39503/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-39503
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-39503
- OSV: https://osv.dev/vulnerability/CVE-2024-39503

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-39503/
Summaries are generated and may contain mistakes; the official description above is the record.