Cisco IOS and IOS XE Group Encrypted Transport VPN Out-of-Bounds Write Vulnerability
Cisco IOS and IOS XE contain an out-of-bounds write vulnerability in the Group Encrypted Transport VPN (GET VPN) feature that could allow an authenticated, remote attacker who has administrative control of either a group member or a key server to execute malicious code or cause a device to crash.
- Vendor
- Cisco
- Product
- IOS and IOS XE
- CVSS
- 6.6
- EPSS (exploit probability)
- 2.5%
- Status
- kev
- CISA patch-by (BOD 22-01)
- Added to KEV
Is CVE-2023-20109 being exploited?
Yes. CISA added CVE-2023-20109 to its Known Exploited Vulnerabilities catalog on . CISA only lists a CVE when it has reliable evidence of exploitation in the wild.
FIRST's EPSS model puts the probability of exploitation activity in the next 30 days at 2.5% (scored October 29, 2026).
- CISA KEV[ LISTED ]
- ENISA EUVD (exploited)[ — ]
- CIRCL KEV[ — ]
Catalog snapshot 2026-11-13. Full cross-catalog view: /kev-comparison
CVE-2023-20109 timeline
Every event links to its source. Catalog dates are each catalog's own; day offsets count from NVD publication. Data: JSON
What to do
CISA required actionApply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
US federal civilian agencies must remediate by (21 days after listing) under BOD 22-01. Everyone else: that deadline is a sensible upper bound, not a target. Vendor guidance and the NVD record are linked under Source above.
Other Cisco IOS and IOS XE CVEs we track
| CVE / Vulnerability | Severity | CVSS | EPSS | Added to KEV |
|---|---|---|---|---|
| CVE-2025-20352 Cisco IOS and IOS XE Software SNMP Denial of Service and Remote Code Execution Vulnerability | [ HIGH ] | 7.7 | 40.6% | |
| CVE-2017-6742 Cisco IOS and IOS XE Software SNMP Remote Code Execution Vulnerability | [ HIGH ] | 8.8 | 21.3% | |
| CVE-2017-3881 Cisco IOS and IOS XE Remote Code Execution Vulnerability | [ CRITICAL ] | 9.8 | 99.0% | |
| CVE-2018-0173 Cisco IOS and IOS XE Software Improper Input Validation Vulnerability | [ HIGH ] | 8.6 | 7.6% | |
| CVE-2018-0172 Cisco IOS and IOS XE Software Improper Input Validation Vulnerability | [ HIGH ] | 8.6 | 7.8% | |
| CVE-2018-0159 Cisco IOS and XE Software Internet Key Exchange Version 1 Denial-of-Service Vulnerability | [ HIGH ] | 7.5 | 6.9% | |
| CVE-2018-0158 Cisco IOS and XE Software Internet Key Exchange Memory Leak Vulnerability | [ HIGH ] | 8.6 | 7.2% | |
| CVE-2018-0156 Cisco IOS Software and Cisco IOS XE Software Smart Install Denial-of-Service Vulnerability | [ HIGH ] | 7.5 | 9.4% |