CVE-2021-1228

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

MEDIUM

6.5

CVSS Score

Published: February 24, 2021 at 07:30 PM UTC

Updated: June 17, 2026 at 03:31 AM UTC

41 products affected across 1 vendorNx OSNexus 9508Nexus 93120Tx

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Severity

MEDIUM6.5

Exploit prediction

EPSS 0.4%

SSVC

No known exploit

Description

A vulnerability in the fabric infrastructure VLAN connection establishment of Cisco Nexus 9000 Series Fabric Switches in Application Centric Infrastructure (ACI) Mode could allow an unauthenticated, adjacent attacker to bypass security validations and connect an unauthorized server to the infrastructure VLAN. This 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 crafted LLDP packet on the adjacent subnet to an affected device. 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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Nx OS · Cisconpm

95%

11.0(1b)11.0(1c)11.0(1d)11.0(1e)11.0(2j)11.0(2m)11.0(3f)11.0(3i)11.0(3k)11.0(3n)11.0(3o)11.0(4g)11.0(4h)11.0(4o)11.0(4q)11.1(1j)11.1(1o)11.1(1r)11.1(1s)11.1(2h)11.1(2i)11.1(3f)11.1(4e)11.1(4f)11.1(4g)11.1(4i)11.1(4l)11.1(4m)11.2(1i)11.2(1k)11.2(1m)11.2(2g)11.2(2h)11.2(2i)11.2(2j)11.2(3c)11.2(3e)11.2(3h)11.2(3m)11.3(1g)11.3(1h)11.3(1i)11.3(1j)11.3(2f)11.3(2h)11.3(2i)11.3(2j)11.3(2k)12.0(1m)12.0(1n)12.0(1o)12.0(1p)12.0(1q)12.0(1r)12.0(2f)12.0(2g)12.0(2h)12.0(2l)12.0(2m)12.0(2n)12.0(2o)12.1(1h)12.1(1i)12.1(2e)12.1(2g)12.1(2k)12.1(3g)12.1(3h)12.1(3j)12.1(4a)12.2(1k)12.2(1n)12.2(1o)12.2(2e)12.2(2f)12.2(2i)12.2(2j)12.2(2k)12.2(2q)12.2(3j)12.2(3p)12.2(3r)12.2(3s)12.2(3t)12.2(4f)12.2(4p)12.2(4q)12.2(4r)12.3(1e)12.3(1f)12.3(1i)12.3(1l)12.3(1o)12.3(1p)13.0(1k)13.0(2h)13.0(2k)13.0(2n)13.1(1i)13.1(2m)13.1(2o)13.1(2p)13.1(2q)13.1(2s)13.1(2t)13.1(2u)13.1(2v)13.2(1l)13.2(1m)13.2(2l)13.2(2o)13.2(3i)13.2(3j)13.2(3n)13.2(3o)13.2(3r)13.2(3s)13.2(41d)13.2(4d)13.2(4e)13.2(5d)13.2(5e)13.2(5f)13.2(6i)13.2(7f)13.2(7k)13.2(8d)13.2(9b)13.2(9f)13.2(9h)14.0(1h)14.0(2c)14.0(3c)14.0(3d)14.1(1i)14.1(1j)14.1(1k)14.1(1l)14.1(2g)14.1(2m)14.1(2o)14.1(2s)14.1(2u)14.1(2w)14.1(2x)14.2(1i)14.2(1j)14.2(1l)14.2(2e)14.2(2f)14.2(3j)14.2(3l)14.2(3n)14.2(3q)14.2(4i)14.2(4k)14.2(4o)14.2(4p)14.2(5k)15.0(1k)15.0(1l)15.0(2h)

cisco-nexus-9000v (environment) · cisco-nexus-92160yc-x (environment) · cisco-nexus-92300yc (environment) · cisco-nexus-92304qc (environment) · cisco-nexus-92348gc-x (environment) · cisco-nexus-9236c (environment) · cisco-nexus-9272q (environment) · cisco-nexus-93108tc-ex (environment) · cisco-nexus-93108tc-ex-24 (environment) · cisco-nexus-93108tc-fx (environment) · cisco-nexus-93108tc-fx-24 (environment) · cisco-nexus-93120tx (environment) · cisco-nexus-93128tx (environment) · cisco-nexus-9316d-gx (environment) · cisco-nexus-93180lc-ex (environment) · cisco-nexus-93180yc-ex (environment) · cisco-nexus-93180yc-ex-24 (environment) · cisco-nexus-93180yc-fx (environment) · cisco-nexus-93180yc-fx-24 (environment) · cisco-nexus-93180yc-fx3 (environment) · cisco-nexus-93180yc-fx3s (environment) · cisco-nexus-93216tc-fx2 (environment) · cisco-nexus-93240yc-fx2 (environment) · cisco-nexus-9332c (environment) · cisco-nexus-9332pq (environment) · cisco-nexus-93360yc-fx2 (environment) · cisco-nexus-9336c-fx2 (environment) · cisco-nexus-9336c-fx2-e (environment) · cisco-nexus-9336pq-aci-spine (environment) · cisco-nexus-9348gc-fxp (environment) · cisco-nexus-93600cd-gx (environment) · cisco-nexus-9364c (environment) · cisco-nexus-9364c-gx (environment) · cisco-nexus-9372px (environment) · cisco-nexus-9372px-e (environment) · cisco-nexus-9372tx (environment) · cisco-nexus-9372tx-e (environment) · cisco-nexus-9396px (environment) · cisco-nexus-9396tx (environment) · cisco-nexus-9508 (environment)

Nexus 9000V · Ciscodevice

80%

All versions

Nexus 92160Yc-X · Ciscodevice

80%

All versions

Nexus 92300Yc · Ciscodevice

80%

All versions

Nexus 92304Qc · Ciscodevice

80%

All versions