# CVE-2017-12231: Cisco IOS Software Network Address Translation Denial-of-Service

> Remote attackers can crash Cisco IOS devices by sending crafted H.323 RAS packets, causing a denial of service.

- **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:** Yes, since 3 Mar 2022 (CISA KEV)
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 28 Sep 2017
- **Updated:** 14 Jan 2026
- **Also known as:** GHSA-83rp-43rf-7hmv

## What is CVE-2017-12231?

CVE-2017-12231 is a high-severity denial of service vulnerability in Cisco Ios, published on 28 Sep 2017. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A vulnerability in the implementation of Network Address Translation (NAT) functionality in Cisco IOS 12.4 through 15.6 could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to the improper translation of H.323 messages that use the Registration, Admission, and Status (RAS) protocol and are sent to an affected device via IPv4 packets. An attacker could exploit this vulnerability by sending a crafted H.323 RAS packet through an affected device. A successful exploit could allow the attacker to cause the affected device to crash and reload, resulting in a DoS condition. This vulnerability affects Cisco devices that are configured to use an application layer gateway with NAT (NAT ALG) for H.323 RAS messages. By default, a NAT ALG is enabled for H.323 RAS messages. Cisco Bug IDs: CSCvc57217.

Weakness: CWE-399

## Which versions are affected by CVE-2017-12231?

It affects 1 product.


Products: Cisco Ios.

## How do I fix CVE-2017-12231?

No fix has been published for CVE-2017-12231 yet. Limit exposure of the affected software until one is available. US federal agencies must fix it by 24 Mar 2022.

## Is CVE-2017-12231 being exploited?

Yes. Attackers have exploited CVE-2017-12231 in the wild since at least 3 Mar 2022.

## 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-2017-12231 and fix it if it is affected.

What it is: CVE-2017-12231 is a high-severity denial of service vulnerability in Cisco Ios, published on 28 Sep 2017. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: Yes. Attackers have exploited CVE-2017-12231 in the wild since at least 3 Mar 2022.

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-2017-12231/ (Markdown: https://insights.sbomify.com/CVE-2017-12231/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2017-12231
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2017-12231
- OSV: https://osv.dev/vulnerability/CVE-2017-12231

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From sbomify Insights: https://insights.sbomify.com/CVE-2017-12231/
Summaries are generated and may contain mistakes; the official description above is the record.