# CVE-2009-2473: Denial of service in n/a

> Attackers can cause denial of service via crafted XML documents exploiting entity expansion recursion in the neon library when expat is used.

- **Severity:** Medium 4.3 (`AV:N/AC:M/Au:N/C:N/I:N/A:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 21 Aug 2009
- **Updated:** 7 Aug 2024
- **Also known as:** GHSA-9vc6-7j3x-7x4v, RHSA-2013:0131

## What is CVE-2009-2473?

CVE-2009-2473 is a medium-severity denial of service vulnerability in n/a, published on 21 Aug 2009. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

neon before 0.28.6, when expat is used, does not properly detect recursion during entity expansion, which allows context-dependent attackers to cause a denial of service (memory and CPU consumption) via a crafted XML document containing a large number of nested entity references, a similar issue to CVE-2003-1564.

Weakness: CWE-399

## Which versions are affected by CVE-2009-2473?

It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `gnome-vfs2` | Red Hat:enterprise_linux:5::client | All versions | 0:2.16.2-10.el5 |
| `gnome-vfs2-debuginfo` | Red Hat:enterprise_linux:5::client | All versions | 0:2.16.2-10.el5 |
| `gnome-vfs2-smb` | Red Hat:enterprise_linux:5::client | All versions | 0:2.16.2-10.el5 |
| `gnome-vfs2` | Red Hat:enterprise_linux:5::client_workstation | All versions | 0:2.16.2-10.el5 |
| `gnome-vfs2-debuginfo` | Red Hat:enterprise_linux:5::client_workstation | All versions | 0:2.16.2-10.el5 |
| `gnome-vfs2-devel` | Red Hat:enterprise_linux:5::client_workstation | All versions | 0:2.16.2-10.el5 |
| `gnome-vfs2` | Red Hat:enterprise_linux:5::server | All versions | 0:2.16.2-10.el5 |
| `gnome-vfs2-debuginfo` | Red Hat:enterprise_linux:5::server | All versions | 0:2.16.2-10.el5 |
| `gnome-vfs2-devel` | Red Hat:enterprise_linux:5::server | All versions | 0:2.16.2-10.el5 |
| `gnome-vfs2-smb` | Red Hat:enterprise_linux:5::server | All versions | 0:2.16.2-10.el5 |

Products: Webdav Neon.

## How do I fix CVE-2009-2473?

Upgrade to a fixed version.

## Is CVE-2009-2473 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2009-2473 exists.

Public exploit code:

- Expat 2.0.1 - UTF-8 Character XML Parsing Remote Denial of Service (exploitdb)

## Other vulnerabilities in n/a

- [CVE-2008-3746](https://insights.sbomify.com/CVE-2008-3746/): Null dereference in n/a (medium 4.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2009-2473 and fix it if it is affected.

What it is: CVE-2009-2473 is a medium-severity denial of service vulnerability in n/a, published on 21 Aug 2009. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2009-2473 exists.

Affected product: n/a. 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-2009-2473/ (Markdown: https://insights.sbomify.com/CVE-2009-2473/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2009-2473
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2009-2473
- OSV: https://osv.dev/vulnerability/CVE-2009-2473

---
From sbomify Insights: https://insights.sbomify.com/CVE-2009-2473/
Summaries are generated and may contain mistakes; the official description above is the record.