# CVE-2023-1206: Denial of service in Kernel

> A local or high-bandwidth attacker can cause excessive CPU usage in the Linux kernel via IPv6 SYN floods, leading to denial of service.

- **Severity:** Medium 5.7 (`CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:N/I:N/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:** 30 Jun 2023
- **Updated:** 14 Oct 2026
- **Also known as:** AZL-27382, DEBIAN-CVE-2023-1206, GHSA-36wf-hpjh-x3fr, UBUNTU-CVE-2023-1206

## What is CVE-2023-1206?

CVE-2023-1206 is a medium-severity denial of service vulnerability in Fedoraproject Fedora, published on 30 Jun 2023. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A hash collision flaw was found in the IPv6 connection lookup table in the Linux kernel’s IPv6 functionality when a user makes a new kind of SYN flood attack. A user located in the local network or with a high bandwidth connection can increase the CPU usage of the server that accepts IPV6 connections up to 95%.

Weakness: CWE-400 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2023-1206?

It affects 3 products.


Products: Fedoraproject Fedora, Linux kernel, Redhat Enterprise Linux.

## How do I fix CVE-2023-1206?

Apply the vendor's patch.

## Is CVE-2023-1206 being exploited?

There is no known exploitation of CVE-2023-1206 in the wild and no public exploit code.

Public exploit code:

- 3 linux kernel bugs chains to do secure comm app using side channel to establish key and establish covert channe; (github_poc): https://github.com/SpiralBL0CK/CVE-2023-1206-CVE-2025-40040-CVE-2024-49882

## Other vulnerabilities in Fedoraproject Fedora

- [CVE-2024-4577](https://insights.sbomify.com/CVE-2024-4577/): PHP-CGI OS Command Injection (critical 9.8, exploited in the wild)
- [CVE-2021-39226](https://insights.sbomify.com/CVE-2021-39226/): Grafana Authentication Bypass (critical 9.8, exploited in the wild)
- [CVE-2019-5544](https://insights.sbomify.com/CVE-2019-5544/): VMware ESXi and Horizon DaaS OpenSLP Heap-Based Buffer Overflow (critical 9.8, exploited in the wild)
- [CVE-2024-4947](https://insights.sbomify.com/CVE-2024-4947/): Google Chromium V8 Type Confusion (critical 9.6, exploited in the wild)
- [CVE-2024-4671](https://insights.sbomify.com/CVE-2024-4671/): Google Chromium Visuals Use-After-Free (critical 9.6, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-1206 and fix it if it is affected.

What it is: CVE-2023-1206 is a medium-severity denial of service vulnerability in Fedoraproject Fedora, published on 30 Jun 2023. 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-2023-1206 in the wild and no public exploit code.

Affected product: Fedoraproject Fedora. 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-2023-1206/ (Markdown: https://insights.sbomify.com/CVE-2023-1206/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-1206
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-1206
- OSV: https://osv.dev/vulnerability/CVE-2023-1206

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-1206/
Summaries are generated and may contain mistakes; the official description above is the record.