CVE-2023-20109

Cisco IOS and IOS XE: Group Encrypted Transport VPN Out-of-Bounds Write

As of , CVE-2023-20109 in Cisco IOS and IOS XE is on CISA's list of exploited vulnerabilities: CISA listed it on . Our patch-first group: Patch soon.

Exploited
Yes: CISA listed it on 10 October 2023
US federal deadline
31 October 202321 days after CISA listed it. US federal civilian agencies must fix it by then.
Used in ransomware campaigns
Not known to CISA
EPSS score
0.02Higher than 84% of the CVEs EPSS scores. EPSS estimates the chance of exploitation activity in the next 30 days.
EPSS when listed
0.00 on 10 October 2023EPSS on the day CISA listed it.
Public exploit
None foundNeither Metasploit nor Exploit-DB lists one.
Fix
Vendor advice: sec.cloudapps.cisco.comLinks below, from CISA's entry.

What CISA says to do

Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

CISA's required action

What the flaw is

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.

CISA's description

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.

The CVE record's description, from cisco

CVE published
27 September 2023
Assigned by
cisco
CVSS
6.6 Medium (CVSS 3.1, from the CNA)
CWE-787
Out-of-bounds Write
CISA SSVC, exploitation
active
CISA SSVC, automatable
no
CISA SSVC, technical impact
total

Timeline

  1. The CVE record was published.
  2. CISA added it to its list of exploited vulnerabilities.
  3. The US federal deadline to fix it.

IOS and IOS XE: other exploited entries

VulnerabilityProductOur groupListedDeadlineEPSS
CVE-2017-3881Remote Code ExecutionCisco IOS and IOS XEPatch this weekMetasploit module; EPSS 0.990.99
CVE-2018-0171Software Smart Install Remote Code ExecutionCisco IOS and IOS XEPatch this weekEPSS 0.990.99
CVE-2025-20352Software SNMP Denial of Service and Remote Code ExecutionCisco IOS and IOS XEPatch soon0.39

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