# CVE-2017-12237: Cisco IOS and IOS XE Software Internet Key Exchange Denial-of-Service

> Remote attackers can cause denial of service on Cisco IOS devices by sending specific IKEv2 packets when ISAKMP is enabled.

- **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:** 12 Jan 2026
- **Also known as:** GHSA-pcwh-xxqr-qw2j

## What is CVE-2017-12237?

CVE-2017-12237 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 Internet Key Exchange Version 2 (IKEv2) module of Cisco IOS 15.0 through 15.6 and Cisco IOS XE 3.5 through 16.5 could allow an unauthenticated, remote attacker to cause high CPU utilization, traceback messages, or a reload of an affected device that leads to a denial of service (DoS) condition. The vulnerability is due to how an affected device processes certain IKEv2 packets. An attacker could exploit this vulnerability by sending specific IKEv2 packets to an affected device to be processed. A successful exploit could allow the attacker to cause high CPU utilization, traceback messages, or a reload of the affected device that leads to a DoS condition. This vulnerability affects Cisco devices that have the Internet Security Association and Key Management Protocol (ISAKMP) enabled. Although only IKEv2 packets can be used to trigger this vulnerability, devices that are running Cisco IOS Software or Cisco IOS XE Software are vulnerable when ISAKMP is enabled. A device does not need to be configured with any IKEv2-specific features to be vulnerable. Many features use IKEv2, including different types of VPNs such as the following: LAN-to-LAN VPN; Remote-access VPN, excluding SSL VPN; Dynamic Multipoint VPN (DMVPN); and FlexVPN. Cisco Bug IDs: CSCvc41277.

Weakness: CWE-399

## Which versions are affected by CVE-2017-12237?

It affects 2 products.


Products: Cisco Ios, Cisco Ios Xe.

## How do I fix CVE-2017-12237?

No fix has been published for CVE-2017-12237 yet. Limit exposure of the affected software until one is available. US federal agencies must fix it by 24 Mar 2022.

## Is CVE-2017-12237 being exploited?

Yes. Attackers have exploited CVE-2017-12237 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-2017-12237 and fix it if it is affected.

What it is: CVE-2017-12237 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-2017-12237 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-2017-12237/ (Markdown: https://insights.sbomify.com/CVE-2017-12237/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2017-12237
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2017-12237
- OSV: https://osv.dev/vulnerability/CVE-2017-12237

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From sbomify Insights: https://insights.sbomify.com/CVE-2017-12237/
Summaries are generated and may contain mistakes; the official description above is the record.