Security Advisory 0217

Date: November 10, 2026

Revision	Date	Changes
1.0	November 10, 2026	Initial release

The CVE-ID tracking this issue: CVE-2026-120977
CVSSv3.1 Base Score: 8.2 (CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:N)
CVSSv4.0 Base Score: 7.1 (CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:L/SI:H/SA:N)
Common Weakness Enumeration: CWE-807: Reliance on Untrusted Inputs in a Security Decision
This vulnerability is being tracked by BUG 2048764(EOS), BUG 2069205(DMF)

Description

On affected platforms running Arista EOS with 802.1X with Dynamic Host Configuration Protocol (DHCP) device profiling enabled, a network-adjacent attacker can send a crafted DHCP packet to force the device to record a spoofed device profile. This may potentially allow the authenticated supplicant to acquire unauthorized access to a network segment with elevated privileges.

This issue was discovered internally by Arista, and the company is not aware of any malicious exploitation of this vulnerability in customer networks.

Vulnerability Assessment

Platform and Software Applicability Note

To determine actual exposure, operators should first check their software versions against the "Affected Software" list below. If your software release is not listed, your deployment is not vulnerable, regardless of the hardware platform in use.

Affected Software

EOS Versions

4.36.2F and earlier release in 4.36.x train
4.35.5M and earlier release in 4.35.x train
4.34.7M and earlier release in 4.34.x train
4.33.9M and earlier release in 4.33.x train
All releases in the 4.32.x train
All releases in the End of Support software release train 4.31.x starting from 4.31.2F

Affected Platforms

The following products are affected by this vulnerability:

Arista EOS-based products:

710 Series
720D Series
720XP/722XPM Series
750X Series
7010TX Series
7020R/R4 Series
7260X/X3 Series
7280R/R2/R3/R4 Series
7050X3/X4 Series
7060X/X2/X4/X5/X6/XE7 Series
7300X/X3 Series
7320X Series
7358X4 Series
7368X4 Series
7388X5 Series
7500R/R2/R3 Series
7700R4 Series
7800R3/R4 Series

The following product versions and platforms are not affected by this vulnerability:

Arista EOS-based products:

77130 Series running EOS
7170 Series
AWE 5000 Series
AWE 7200R Series
ZTX-7200 Series
CloudEOS
cEOS-lab
vEOS-lab
CloudVision eXchange, virtual or physical appliance

Wi-Fi Access Points
CloudVision CUE cloud service delivery
CloudVision Portal on-premises, virtual appliance or physical appliance (including the CV-CUE on premises software)
CloudVision Appliance Software
CloudVision as-a-Service
CloudVision AGNI - Cloud service delivery
CloudVision AGNI - Virtual or physical appliance
Arista Converged Cloud Fabric (formerly Big Switch BCF)
DANZ Monitoring Fabric (DMF) - Controller Appliance
DANZ Monitoring Fabric (DMF) - Analytics Node Appliance
DANZ Monitoring Fabric (DMF) - Recorder Node Appliance
DANZ Monitoring Fabric (DMF) - Service Node Appliance
Arista Multi Cloud Director (formerly Big Switch MCD)
Arista Network Detection and Response (NDR) Security Platform (Formerly Awake NDR)
Arista Edge Threat Management - Arista NG Firewall and Arista Micro Edge (Formerly Untangle)
Arista NetVisor OS, Arista NetVisor UNUM, and Insight Analytics (Formerly Pluribus)
VeloCloud Orchestrator (Formerly VeloCloud Orchestrator by Broadcom)
VeloCloud Gateway (Formerly VeloCloud Gateway by Broadcom)
VeloCloud Edge (Formerly VeloCloud Edge by Broadcom)

Required Configuration for Exploitation

In order to be vulnerable to CVE-2026-120977, the following condition must be met:

802.1X global system authentication control is configured
at least one interface is configured as the 802.1X authenticator
at least one DHCP profiling option is configured
802.1X RADIUS accounting is enabled

A supplicant vulnerable to this may be EAPOL or MBA. A sample configuration is given below:

switch#show running-config
aaa accounting dot1x default start-stop group radius
 
dot1x
   ! Any one of the following DHCP profiling options is sufficient;
   ! enabling all three is not required.
   radius av-pair dhcp hostname
   radius av-pair dhcp parameter-request-list
   radius av-pair dhcp vendor-class-id
 
interface Ethernet5
   switchport mode trunk
   spanning-tree portfast edge
   dot1x pae authenticator
   dot1x port-control auto
dot1x system-auth-control

Indicators of Compromise

To determine if this vulnerability has been exploited, inspect RADIUS Accounting messages for mismatched or unexpected supplicant device profiles, which may lead to incorrect AAA authorization policies or unintended Session Change of Authorization (CoA).

switch#show dot1x hosts mac <supplicant_mac> accounting

Mitigation

There is no workaround to prevent this behaviour.

Resolution

The recommended resolution is to upgrade to a remediated software version at your earliest convenience. Arista recommends customers move to the latest version of each release that contains all the fixes listed below. For more information about upgrading see EOS User Manual: Upgrades and Downgrades

CVE-2026-120977 has been fixed in the following releases:

4.37.0F and later release in 4.37.x train
4.36.3M and later release in 4.36.x train
4.35.6M and later release in 4.35.x train
4.34.8M and later release in 4.34.x train
4.33.10M and later release in 4.33.x train

Hotfix

No hotfix is available for this issue

For More Information

If you require further assistance, or if you have any further questions regarding this security notice, please contact the Arista Networks Technical Assistance Center (TAC) by one of the following methods:

Open a Service Request
By email: This email address is being protected from spambots. You need JavaScript enabled to view it.
By telephone: List of regional telephone numbers

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