# CVE-2011-4012: Denial of service in n/a

> Remote attackers can cause a denial of service on Cisco IOS devices using PFC3C by exploiting ICMPv6 ACL fragment entry handling.

- **Severity:** Critical 9.3 (`AV:N/AC:M/Au:N/C:C/I:C/A:C`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 2 May 2012
- **Updated:** 6 Aug 2024
- **Also known as:** GHSA-rcm6-ccwh-xh5v

## What is CVE-2011-4012?

CVE-2011-4012 is a critical denial of service vulnerability in Cisco Ios, published on 2 May 2012. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Cisco IOS 12.0, 15.0, and 15.1, when a Policy Feature Card 3C (PFC3C) is used, does not create a fragment entry during processing of an ICMPv6 ACL, which has unspecified impact and remote attack vectors, aka Bug ID CSCtj90091.

## Which versions are affected by CVE-2011-4012?

It affects 1 product.


Products: Cisco Ios.

## How do I fix CVE-2011-4012?

No fix has been published for CVE-2011-4012 yet. Limit exposure of the affected software until one is available.

## Is CVE-2011-4012 being exploited?

There is no known exploitation of CVE-2011-4012 in the wild and no public exploit code.

## Other vulnerabilities in Cisco Ios

- [CVE-2017-12240](https://insights.sbomify.com/CVE-2017-12240/): Cisco IOS and IOS XE Software DHCP Remote Code Execution (critical 9.8, exploited in the wild)
- [CVE-2017-3881](https://insights.sbomify.com/CVE-2017-3881/): Cisco IOS and IOS XE Remote Code Execution (critical 9.8, exploited in the wild)
- [CVE-2018-0167](https://insights.sbomify.com/CVE-2018-0167/): Cisco IOS, XR, and XE Software Buffer Overflow (high 8.8, exploited in the wild)
- [CVE-2017-6736](https://insights.sbomify.com/CVE-2017-6736/): Cisco IOS and IOS XE Software SNMP Remote Code Execution (high 8.8, exploited in the wild)
- [CVE-2017-6737](https://insights.sbomify.com/CVE-2017-6737/): Cisco IOS and IOS XE Software SNMP Remote Code Execution (high 8.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2011-4012 and fix it if it is affected.

What it is: CVE-2011-4012 is a critical denial of service vulnerability in Cisco Ios, published on 2 May 2012. 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-2011-4012 in the wild and no public exploit code.

Affected product: Cisco Ios. 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-2011-4012/ (Markdown: https://insights.sbomify.com/CVE-2011-4012/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2011-4012
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2011-4012
- OSV: https://osv.dev/vulnerability/CVE-2011-4012

---
From sbomify Insights: https://insights.sbomify.com/CVE-2011-4012/
Summaries are generated and may contain mistakes; the official description above is the record.