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

Source: https://junglewise.ai/threats/cve-2023-20109-cisco-ios-and-ios-xe-group-encrypted-transport-vpn-out-of-bounds  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2023-10-10. Updated: 2026-05-09  
License: CC BY 4.0 with a link back

CVE-2023-20109 · Severity: critical · CVSS 6.6 · Exploited in the wild · Published 2023-10-10

An out-of-bounds write vulnerability in the Group Encrypted Transport VPN (GET VPN) feature of Cisco IOS and IOS XE Software allows authenticated remote attackers with administrative control of a key server or group member to execute arbitrary code or cause a denial of service. The flaw stems from insufficient validation of attributes in the GDOI and G-IKEv2 protocols.

Technologies: [Cisco IOS](https://junglewise.ai/threats/technologies/ios), [Cisco IOS XE](https://junglewise.ai/threats/technologies/ios-xe), [Cisco IOS XR](https://junglewise.ai/threats/technologies/ios-xr). Vendors: [Cisco](https://junglewise.ai/threats/vendors/cisco).

## Quick answers

**Is CVE-2023-20109 exploited in the wild?** Yes. CVE-2023-20109 is known to be exploited in the wild, first recorded on 10 October 2023. Treat it as urgent.

**How severe is CVE-2023-20109?** Critical severity, with a CVSS score of 6.6, published 10 October 2023.

**Which products and versions are affected?** Cisco IOS 12.4(22)md, 12.4(22)md1, 12.4(22)md2, 12.4(22)mda, 12.4(22)mda1; Cisco IOS XE.

**Is there a fix for CVE-2023-20109?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2023-20109 attacked?** It is attacked over the network, in an operating system.

**Am I affected by CVE-2023-20109?** Check whether you run Cisco IOS, Cisco IOS XE or Cisco IOS XR. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Affected products

- Cisco IOS 12.4(22)md, 12.4(22)md1, 12.4(22)md2, 12.4(22)mda, 12.4(22)mda1
- Cisco IOS XE

## Timeline

- 2023-10-10: disclosed
- 2023-10-10: kev added: Added to CISA Known Exploited Vulnerabilities Catalog
- 2023-10-10: exploited: Reported as exploited in the wild at time of publication.

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