---
title: "CVE-2023-20109: Cisco IOS and IOS XE Group Encrypted Transport VPN Out-of-Bounds Write Vulnerability"
url: https://erroneo.us/security/cve/CVE-2023-20109/
description: "CVE-2023-20109 (Cisco IOS and IOS XE): Exploited in the wild (CISA KEV). A vulnerability in the Cisco Group Encrypted Transport VPN (GET VPN) feature of…"
type: vulnerability-record
section: "Security Digest"
date_published: 2023-09-27
date_modified: 2025-10-21
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2023-20109"
kev: true
cvss: 6.6
epss: 0.02484
license: All rights reserved. Quote with attribution and a link.
---

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

**Signal:** Exploited: patch now if you run it. CISA has confirmed exploitation in the wild. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Yes, if you run Cisco IOS and IOS XE. CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2023-10-10, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2023-10-31 ; treat that as the outer limit, not the target.
- EPSS 2.5% , percentile 84: FIRST’s model estimates a 2.5% chance of exploitation activity in the next 30 days, higher than 84% of all scored CVEs (elevated). EPSS is a probability, not a verdict.
- Needs an account (high (admin)). Exposure depends on who can log in.

## What it is

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.

## Affected products (CVE record)

- Cisco IOS: 12.4(24)T, 12.4(24)T3, 12.4(22)T1, 12.4(24)T5, 12.4(24)T4, 12.4(22)T, 12.4(24)T8, 12.4(24)T2, 12.4(22)T5, 12.4(22)T4, 12.4(24)T1, 12.4(24)T7
- Cisco Cisco IOS XE Software: 3.7.0S, 3.7.1S, 3.7.2S, 3.7.3S, 3.7.4S, 3.7.5S, 3.7.6S, 3.7.7S, 3.7.4aS, 3.7.2tS, 3.7.0bS, 3.7.1aS

## Severity

- cisco CVSS 3.1: 6.6 `CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H`

## Exploitation

- CISA KEV: added 2023-10-10; federal due date 2023-10-31. Known ransomware use: Unknown.
- CISA required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
- CISA SSVC assessment: exploitation active , automatable no , technical impact total .
- FIRST EPSS (model of 2026-10-21): 2.48% probability of exploitation activity in the next 30 days; percentile 84.

## Sources

- [Listed in CISA KEV notes (sec.cloudapps.cisco.com)](https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-getvpn-rce-g8qR68sx)
- [CVE.org record CVE-2023-20109](https://www.cve.org/CVERecord?id=CVE-2023-20109)
- [NVD entry CVE-2023-20109](https://nvd.nist.gov/vuln/detail/CVE-2023-20109)
- [CISA Known Exploited Vulnerabilities catalog entry](https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-20109)

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Source page: https://erroneo.us/security/cve/CVE-2023-20109/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt