Threats / Cisco / CVE-2023-20109
CVE-2023-20109
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-06-22
Cisco IOS and XE vulnerability
Cisco IOS and IOS XE contain an out-of-bounds write vulnerability in GET VPN that allows authenticated remote attackers with administrative control to execute code or crash devices.
Verdict
Today item — known-exploited.
An authenticated remote attacker with administrative privileges on a group member or key server can exploit an out-of-bounds write flaw to achieve remote code execution or denial of service on affected Cisco routing devices.
01
Is it exploitable?
— the evidence, ranked above the scoreReported exploitation
3 independent public reports of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2023-10-10).
Probability (EPSS)
EPSS 0.02344 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
Affected: Cisco, IOS and IOS XE. Confirm exact fixed builds in the vendor advisory.
Weakness (CWE)
Mapped to CWE-787 Out-of-bounds Write — weakness family: Memory safety.CWE assignment from the public NVD record; the weakness class drives how the flaw is exploited.
02
Who’s exploiting it?
— attribution turns risk into urgencyAttribution not established
No confirmed (advisory-backed) threat-actor attribution is established for this record. Absence of a named actor is not absence of compromise — see Coverage & confidence.
03
Why it matters
— the attack path, told twice: adversary, then board1
Front door — unauthenticated access narrative 1
Attacker
I gain administrative access to a GET VPN group member or key server through credential compromise or insider access.
Business
An insider or compromised administrator account provides the foothold needed to target core network infrastructure.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I craft a malicious packet that triggers an out-of-bounds write in the GET VPN processing logic on a remote device.
Business
The vulnerability allows direct code execution on critical routing devices that manage encrypted traffic flows.
3
Lateral reach — past segmentation narrative 3
Attacker
I execute arbitrary code with device privileges or force a crash to disrupt VPN operations.
Business
Compromise of VPN infrastructure can lead to data exfiltration, network segmentation bypass, or extended service outages.
04
What to do
— defensible action- Remediate per the vendor advisory — confirm the fixed build for your version and verify exposure.1
Say it to the boardA vulnerability with this evidence profile is a defensible budget line, not a backlog ticket — fund the change against the proof above.
05