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

Medium severity, CVSS 6.6. Actively exploited: in CISA KEV since 2023-10-10. EPSS: 2.5% chance of exploitation in the next 30 days.

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

• Cisco IOS: version 12.4(22)md only; version 12.4(22)md1 only; version 12.4(22)md2 only; version 12.4(22)mda only; version 12.4(22)mda1 only; version 12.4(22)mda2 only; …
• Cisco IOS XE: version 3.3.0sg only; version 3.3.1sg only; version 3.3.2sg only; version 3.4.0sg only; version 3.4.1sg only; version 3.4.2sg only; …

Published 2023-09-27. Last modified 2026-06-17.