How severe is CVE-2023-20109?

CVE-2023-20109 has a CVSS score of 6.6/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2023-20109?

Affected package information for CVE-2023-20109 is not yet fully mapped. Check the official advisory links for details.

How do I fix CVE-2023-20109?

No fixed version has been published for CVE-2023-20109 yet. Monitor the advisory for updates, apply mitigations recommended by the vendor, and use O3 Security to track when a fix becomes available in your stack.

Is CVE-2023-20109 actively exploited in the wild?

Yes. There are 2 known exploit references for CVE-2023-20109, including 2 in-the-wild exploitations observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2023-20109?

CVE-2023-20109 has an EPSS (Exploit Prediction Scoring System) score of 0.6%, placing it in the 71th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

Is CVE-2023-20109 in the CISA Known Exploited Vulnerabilities catalog?

Yes. CVE-2023-20109 (Cisco IOS and IOS XE Group Encrypted Transport VPN Out-of-Bounds Write Vulnerability) was added to CISA's Known Exploited Vulnerabilities (KEV) catalog on 2023-10-10. CISA required all US federal civilian agencies to remediate this vulnerability by 2023-10-31. The required action was: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable. Being listed in the KEV catalog is the strongest possible confirmation of active exploitation — treat this as a critical priority.

What type of vulnerability is CVE-2023-20109?

CVE-2023-20109 is classified as Out-of-bounds Write (CWE-787). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

Which products and versions are affected by CVE-2023-20109?

CVE-2023-20109 affects cisco ios (674 versions, e.g. 12.4\(22\)md, 12.4\(22\)md1, 12.4\(22\)md2…); cisco ios xe (364 versions, e.g. 3.3.0sg, 3.3.1sg, 3.3.2sg…). Check the affected-products list on this page against your deployed version to confirm exposure.

When was CVE-2023-20109 published, and has it been updated?

CVE-2023-20109 was published on September 27, 2023 and was last updated on October 28, 2025. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CISA KEV·Added 2023-10-10 — agencies required to remediate by 2023-10-31

CVE-2023-20109

MEDIUM

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…

Published

Sep 27, 2023

Updated

Oct 28, 2025

Affected

0 pkgs

Patched

None yet

Exploits

2 known

EPSS Exploitation Probability

via FIRST.org ↗

0.6%probability of exploitation in next 30 days

Lower Risk71th percentile0.00%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Description

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

2 products · 1038 configurations

ioscisco

674 versions

12.4\(22\)md12.4\(22\)md112.4\(22\)md212.4\(22\)mda12.4\(22\)mda112.4\(22\)mda212.4\(22\)mda312.4\(22\)mda412.4\(22\)mda512.4\(22\)mda612.4\(22\)t12.4\(22\)t1

ios xecisco

364 versions

3.3.0sg3.3.1sg3.3.2sg3.4.0sg3.4.1sg3.4.2sg3.4.3sg3.4.4sg3.4.5sg3.4.6sg3.4.7sg3.4.8sg

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

A vulnerability in the Cisco Group Encrypted Transport VPN (GET VPN) fea…

thehackernews.comAPISep 2023

A vulnerability in the Cisco Group Encrypted Transport VPN (GET VPN) fea…

cisa.govCISAOct 2023

Frequently Asked Questions

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 configura

O3 Security · Impact-Aware SCA

Is CVE-2023-20109 in your stack?

O3 detects CVE-2023-20109 across dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

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