# CVE-2009-4272: Denial of service in n/a

> Remote attackers can cause a denial of service via crafted packets triggering IPv4 routing hash collisions and deadlocks in the Linux kernel.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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 Jan 2010
- **Updated:** 7 Aug 2024
- **Also known as:** GHSA-w5pr-8rvr-3pcp

## What is CVE-2009-4272?

CVE-2009-4272 is a high-severity denial of service vulnerability in Linux kernel, published on 27 Jan 2010. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A certain Red Hat patch for net/ipv4/route.c in the Linux kernel 2.6.18 on Red Hat Enterprise Linux (RHEL) 5 allows remote attackers to cause a denial of service (deadlock) via crafted packets that force collisions in the IPv4 routing hash table, and trigger a routing "emergency" in which a hash chain is too long.  NOTE: this is related to an issue in the Linux kernel before 2.6.31, when the kernel routing cache is disabled, involving an uninitialized pointer and a panic.

Weakness: CWE-667 (Improper Locking)

## Which versions are affected by CVE-2009-4272?

It affects 6 products.


Products: Linux kernel, Redhat Enterprise Linux Desktop, Redhat Enterprise Linux Eus, Redhat Enterprise Linux Server, Redhat Enterprise Linux Workstation, Redhat Virtualization.

## How do I fix CVE-2009-4272?

Apply the vendor's patch.

## Is CVE-2009-4272 being exploited?

There is no known exploitation of CVE-2009-4272 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-2009-4272 and fix it if it is affected.

What it is: CVE-2009-4272 is a high-severity denial of service vulnerability in Linux kernel, published on 27 Jan 2010. 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-2009-4272 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-2009-4272/ (Markdown: https://insights.sbomify.com/CVE-2009-4272/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2009-4272
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2009-4272
- OSV: https://osv.dev/vulnerability/CVE-2009-4272

---
From sbomify Insights: https://insights.sbomify.com/CVE-2009-4272/
Summaries are generated and may contain mistakes; the official description above is the record.