Detections
Analytics

Arista Networks EOS Tunnel Decapsulation Improper Validation (SA0137)

medium Nessus Plugin ID 321106

Language:

Synopsis

The Arista Networks EOS device is affected by an incomplete comparison with missing factors vulnerability in its tunnel decapsulation handling.

Description

On affected platforms running Arista EOS where a tunnel decapsulation configuration - such as VXLAN (Virtual Extensible LAN), decap-groups, or a GRE (Generic Routing Encapsulation) tunnel interface - is present, the switch will incorrectly decapsulate and forward other unexpected tunneled packets with a destination IP matching its configured decapsulation IP. This occurs because the switch does not verify the tunnel protocol type, potentially leading to the unexpected processing of non-configured tunnel traffic.

Note that Arista has stated that no software upgrade path or hotfix is planned to address this issue due to the risk of breaking existing configurations. The only remediation is the configuration-based mitigation (ACLs) referenced in the vendor advisory.

Please see the referenced Arista Security Advisory for more information.

Solution

There is no fixed version. Apply the access control list (ACL) mitigations referenced in the vendor advisory to restrict the tunnel protocols accepted at the configured decapsulation IP.

See Also

http://www.nessus.org/u?00ef8e0a

Plugin Details

Severity: Medium

ID: 321106

File Name: arista_eos_sa0137.nasl

Version: 1.4

Type: Combined

Family: Misc.

Published: 6/15/2026

Updated: 6/26/2026

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.2

Percentile: 53.64

CVSS v2

Risk Factor: Medium

Base Score: 5

Temporal Score: 4.1

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:P/A:N

CVSS Score Source: CVE-2026-7473

CVSS v3

Risk Factor: Medium

Base Score: 5.8

Temporal Score: 5.4

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N

Temporal Vector: CVSS:3.0/E:F/RL:O/RC:C

CVSS v4

Risk Factor: Medium

Base Score: 6.9

Threat Score: 6.9

Threat Vector: CVSS:4.0/E:A

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N

Vulnerability Information

CPE: cpe:/o:arista:eos

Required KB Items: Host/Arista-EOS/Version, Host/Arista-EOS/model

Exploit Available: true

Exploit Ease: Exploits are available

Vulnerability Publication Date: 5/5/2026

CISA Known Exploited Vulnerability Due Dates: 6/23/2026

Reference Information

CVE: CVE-2026-7473

IAVA: 2026-A-0625