Cisco Nexus 9000 Series Fabric Switches ACI Mode Fabric Infrastructure VLAN Unauthorized Access Vulnerability

published 2019-07-04 7 y ago modified 2026-06-17 4 mo ago also EUVD-2019-10447

cvss: 7.4; version 3.0, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.6%; EPSS 0.6% chance of exploitation in 30 days, percentile 50%
public exploits: 0; none known

A vulnerability in the fabric infrastructure VLAN connection establishment of the Cisco Nexus 9000 Series Application Centric Infrastructure (ACI) Mode Switch Software could allow an unauthenticated, adjacent attacker to bypass security validations and connect an unauthorized server to the infrastructure VLAN. The vulnerability is due to insufficient security requirements during the Link Layer Discovery Protocol (LLDP) setup phase of the infrastructure VLAN. An attacker could exploit this vulnerability by sending a malicious LLDP packet on the adjacent subnet to the Cisco Nexus 9000 Series Switch in ACI mode. A successful exploit could allow the attacker to connect an unauthorized server to the infrastructure VLAN, which is highly privileged. With a connection to the infrastructure VLAN, the attacker can make unauthorized connections to Cisco Application Policy Infrastructure Controller (APIC) services or join other host endpoints.

Patch / fix

fixed in 1

Cisco Cisco NX-OS System Software in ACI Mode 11.0.1b 14.1(2g)

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 23 mo ago (2024-11-21)

Exploit prediction

0.63% chance of exploitation in the next 30 days, higher than 50% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.0	7.4	CVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N
NVD	3.1	6.5	CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
NVD	2.0	3.3	AV:A/AC:L/Au:N/C:N/I:P/A:N

Affected products

Cisco Cisco NX-OS System Software in ACI Mode 11.0.1b

Classification

Weakness

CWE-284 Improper Access Control

References

tools.cisco.com /security/center/content/CiscoSecurityAdvisory/cisco-sa-20190703-n9kaci-bypass
vendor-advisory
securityfocus.com /bid/109052
vdb-entry, third-party-advisory

Sources

CVE List CVE-2019-1890
NVD CVE-2019-1890

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Summary