# CVE-2024-53206: tcp: Fix use-after-free of nreq in reqsk_timer_handler().

> A use-after-free vulnerability in the Linux kernel TCP stack allows attackers to potentially execute code or cause a denial of service.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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:** 27 Dec 2024
- **Updated:** 5 Aug 2026
- **Also known as:** AZL-55564, BELL-CVE-2024-53206, DEBIAN-CVE-2024-53206, GHSA-hx9w-rm9x-mqpr, UBUNTU-CVE-2024-53206

## What is CVE-2024-53206?

CVE-2024-53206 is a critical use after free vulnerability in Linux kernel, published on 27 Dec 2024. 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:

tcp: Fix use-after-free of nreq in reqsk_timer_handler().

The cited commit replaced inet_csk_reqsk_queue_drop_and_put() with
__inet_csk_reqsk_queue_drop() and reqsk_put() in reqsk_timer_handler().

Then, oreq should be passed to reqsk_put() instead of req; otherwise
use-after-free of nreq could happen when reqsk is migrated but the
retry attempt failed (e.g. due to timeout).

Let's pass oreq to reqsk_put().

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2024-53206?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2024-53206?

Apply the vendor's patch.

## Is CVE-2024-53206 being exploited?

There is no known exploitation of CVE-2024-53206 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-2024-53206 and fix it if it is affected.

What it is: CVE-2024-53206 is a critical use after free vulnerability in Linux kernel, published on 27 Dec 2024. 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-2024-53206 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-2024-53206/ (Markdown: https://insights.sbomify.com/CVE-2024-53206/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-53206
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-53206
- OSV: https://osv.dev/vulnerability/CVE-2024-53206

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-53206/
Summaries are generated and may contain mistakes; the official description above is the record.