# CVE-2023-20109: Cisco IOS and IOS XE Group Encrypted Transport VPN Out-of-Bounds Write

> An authenticated remote attacker with administrative control can execute arbitrary code or cause a denial of service on Cisco IOS devices using GET VPN.

- **Severity:** Medium 6.6 (`CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Yes, since 10 Oct 2023 (CISA KEV)
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 27 Sep 2023
- **Updated:** 21 Oct 2025
- **Also known as:** GHSA-7h8h-8482-vvfh

## What is CVE-2023-20109?

CVE-2023-20109 is a medium-severity memory corruption vulnerability in Cisco Ios, published on 27 Sep 2023. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

A vulnerability in the Cisco Group Encrypted Transport VPN (GET VPN) feature of Cisco IOS Software and Cisco IOS XE Software could allow an authenticated, remote attacker who has administrative control of either a group member or a key server to execute arbitrary code on an affected device or cause the device to crash.

 This vulnerability is due to insufficient validation of attributes in the Group Domain of Interpretation (GDOI) and G-IKEv2 protocols of the GET VPN feature. An attacker could exploit this vulnerability by either compromising an installed key server or modifying the configuration of a group member to point to a key server that is controlled by the attacker. A successful exploit could allow the attacker to execute arbitrary code and gain full control of the affected system or cause the affected system to reload, resulting in a denial of service (DoS) condition. For more information, see the Details ["#details"] section of this advisory.

Weakness: CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2023-20109?

It affects 2 products.


Products: Cisco Ios, Cisco Ios Xe.

## How do I fix CVE-2023-20109?

No fix has been published for CVE-2023-20109 yet. Limit exposure of the affected software until one is available. US federal agencies must fix it by 31 Oct 2023.

## Is CVE-2023-20109 being exploited?

Yes. Attackers have exploited CVE-2023-20109 in the wild since at least 10 Oct 2023.

## 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-2023-20109 and fix it if it is affected.

What it is: CVE-2023-20109 is a medium-severity memory corruption vulnerability in Cisco Ios, published on 27 Sep 2023. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: Yes. Attackers have exploited CVE-2023-20109 in the wild since at least 10 Oct 2023.

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-2023-20109/ (Markdown: https://insights.sbomify.com/CVE-2023-20109/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-20109
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-20109
- OSV: https://osv.dev/vulnerability/CVE-2023-20109

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From sbomify Insights: https://insights.sbomify.com/CVE-2023-20109/
Summaries are generated and may contain mistakes; the official description above is the record.