# CVE-2012-5521: Denial of service in quagga

> Attackers can cause a denial of service in the Quagga ospf6d daemon by triggering a flaw in route removal processing.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:A/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:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 25 Nov 2019
- **Updated:** 6 Aug 2024
- **Also known as:** GHSA-r8m3-p659-7pmw, UBUNTU-CVE-2012-5521

## What is CVE-2012-5521?

CVE-2012-5521 is a medium-severity denial of service vulnerability in Debian Debian Linux, published on 25 Nov 2019. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

quagga (ospf6d) 0.99.21 has a DoS flaw in the way the ospf6d daemon performs routes removal

Weakness: CWE-617 (Reachable Assertion)

## Which versions are affected by CVE-2012-5521?

It affects 3 products.


Products: Debian Debian Linux, Quagga Quagga, Redhat Enterprise Linux.

## How do I fix CVE-2012-5521?

No fix has been published for CVE-2012-5521 yet. Limit exposure of the affected software until one is available.

## Is CVE-2012-5521 being exploited?

There is no known exploitation of CVE-2012-5521 in the wild and no public exploit code.

## Other vulnerabilities in Debian Debian Linux

- [CVE-2015-3306](https://insights.sbomify.com/CVE-2015-3306/): ProFTPD Improper Access Control (critical 10.0, exploited in the wild)
- [CVE-2025-49113](https://insights.sbomify.com/CVE-2025-49113/): RoundCube Webmail Deserialization of Untrusted Data (critical 9.9, exploited in the wild)
- [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild)
- [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild)
- [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2012-5521 and fix it if it is affected.

What it is: CVE-2012-5521 is a medium-severity denial of service vulnerability in Debian Debian Linux, published on 25 Nov 2019. 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-2012-5521 in the wild and no public exploit code.

Affected product: Debian Debian Linux. 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-2012-5521/ (Markdown: https://insights.sbomify.com/CVE-2012-5521/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2012-5521
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2012-5521
- OSV: https://osv.dev/vulnerability/CVE-2012-5521

---
From sbomify Insights: https://insights.sbomify.com/CVE-2012-5521/
Summaries are generated and may contain mistakes; the official description above is the record.