CVE-2026-7473: Arista Extensible Operating System

Should you act?

Exploited: patch now if you run it

CISA has confirmed exploitation in the wild. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

Yes, if you run Arista Extensible Operating System. CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2026-06-09, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2026-06-23; treat that as the outer limit, not the target.
EPSS 0.6%, percentile 50: FIRST’s model estimates a 0.6% chance of exploitation activity in the next 30 days, higher than 50% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.

What it is

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 packet 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. This issue has been reported as being exploited in the wild.

CISA’s summary

Arista Extensible Operating System (EOS) contains an incomplete comparison with missing factors vulnerability when the switch incorrectly decapsulate and forwards other unexpected tunneled packet with a destination IP matching its configured decapsulation IP.

Weakness type: CWE-1023.

Product: Arista Extensible Operating System · Assigned by: Arista · Published: 2026-06-05

Affected and fixed versions

Vendor	Product	Affected versions (per CVE record)
Arista Networks	EOS	4.36.0, 4.35.0 <= 4.35, 4.34.0 <= 4.34, 4.33.0 <= 4.33, 4.32.0 <= 4.32, 4.31.0 <= 4.31, <= 4.30

Severity scores

Scored by	CVSS	Score	Vector
Arista	3.1	5.8 Medium	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N`
Arista	4.0	6.9 Medium	`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`

Attack vector: network (remotely reachable)
Attack complexity: low
Attack requirements: none
Privileges required: none (no login)
User interaction: none

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

CISA KEV: added 2026-06-09; federal due date 2026-06-23. Known ransomware use: Unknown.
CISA required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
CISA SSVC assessment: exploitation active, automatable yes, technical impact total.
FIRST EPSS (model of 2026-10-21): 0.65% probability of exploitation activity in the next 30 days; percentile 50.

Timeline

2026-06-05 — CVE record published by Arista
2026-06-09 — Added to CISA’s Known Exploited Vulnerabilities catalog
2026-06-23 — CISA remediation deadline for US federal agencies
2026-10-07 — CVE record last updated

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vendor and project advisories, patches

arista.com arista.com
arista.com arista.com

Vulnerability records

CVE.org record CVE-2026-7473 cve.org
NVD entry CVE-2026-7473 nvd.nist.gov

Government

CISA Known Exploited Vulnerabilities catalog entry cisa.gov

All exploited Arista vulnerabilities · Today’s Security Digest