# CVE-2012-4565: Denial of service in n/a

> Local users can cause a denial of service via divide-by-zero in TCP Illinois congestion control when enabled.

- **Severity:** Medium 4.7 (`AV:L/AC:M/Au:N/C:N/I:N/A:C`)
- **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:** 21 Dec 2012
- **Updated:** 6 Aug 2024
- **Also known as:** DEBIAN-CVE-2012-4565, GHSA-gmmj-v76j-xgxw

## What is CVE-2012-4565?

CVE-2012-4565 is a medium-severity denial of service vulnerability in Linux kernel, published on 21 Dec 2012. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

The tcp_illinois_info function in net/ipv4/tcp_illinois.c in the Linux kernel before 3.4.19, when the net.ipv4.tcp_congestion_control illinois setting is enabled, allows local users to cause a denial of service (divide-by-zero error and OOPS) by reading TCP stats.

Weakness: CWE-189

## Which versions are affected by CVE-2012-4565?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2012-4565?

Upgrade to a fixed version.

## Is CVE-2012-4565 being exploited?

There is no known exploitation of CVE-2012-4565 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-2012-4565 and fix it if it is affected.

What it is: CVE-2012-4565 is a medium-severity denial of service vulnerability in Linux kernel, published on 21 Dec 2012. 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-2012-4565 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-2012-4565/ (Markdown: https://insights.sbomify.com/CVE-2012-4565/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2012-4565
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2012-4565
- OSV: https://osv.dev/vulnerability/CVE-2012-4565

---
From sbomify Insights: https://insights.sbomify.com/CVE-2012-4565/
Summaries are generated and may contain mistakes; the official description above is the record.