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CVE-2026-7473

From Exploited flaws, HARD’s guide to the flaws being used in attacks · Checked
This article is about a flaw in Arista Extensible Operating System. For every flaw being used in attacks, see Exploited flaws; for Arista’s, see Arista flaws being used in attacks.

CVE-2026-7473 is a security flaw in Arista Extensible Operating System. Attackers are using a flaw in Arista Extensible Operating System. The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 9 Jun 2026.[1]

Arista Extensible Operating System is business software or equipment. Most families won’t have it, but attackers break into it to get inside companies, and from there to what those companies hold about their customers, patients and staff. Arista has published a fix or advice.

Description

CISA calls it an incomplete comparison with missing factors in Arista Extensible Operating System. In its words: “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.”[1]

The CVE record adds: “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.”[2]

The underlying weakness is CWE-1023, in MITRE’s list of common software weaknesses.

It scores 5.8 out of 10 on the Common Vulnerability Scoring System, which rates it medium, scored by the organisation that published the CVE using CVSS 3.1.[2]

Affected versions

NVD’s record doesn’t list version ranges for it; Arista’s advisory has them[3]. CISA names the product as Arista Extensible Operating System.

Most families won’t have Arista Extensible Operating System; it’s for whoever looks after IT at work.

Exploitation

CISA added it to its catalog of known exploited vulnerabilities on 9 Jun 2026, 4 days after it was made public. CISA lists a flaw only when it has reliable evidence of it being exploited, and gave US federal agencies until 23 Jun 2026 to fix it.[1]

FIRST’s Exploit Prediction Scoring System, which estimates how likely a flaw is to be used in attacks in the next 30 days from what it sees across the internet, puts it at 1%. That’s in the top 35% of the flaws it scores.[4]

CISA assesses it as automatable: attackers can run it against many targets at once.

CISA doesn’t say who was attacked, or how.

Fix

Arista has published a fix or advice.[3] CISA’s 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.”[1]

  1. Check whether you use it.Arista Extensible Operating System is business software or equipment, so most families won’t have it. If you run a business, or work from home on company equipment, ask whoever looks after your IT.
  2. Send this page to your IT person.Ask them to confirm it’s fixed, or not in use. CISA gave US government agencies until 23 Jun 2026 to fix it.
  3. If it can’t be fixed, take it offline.CISA’s advice when there’s no fix is to stop using the product, or take it off the internet, until there is one.

You can’t fix someone else’s server, but you can watch for what follows a break-in like this: a breach notice, a password reset you didn’t ask for, or a scam message that knows things it shouldn’t. HARD watches for those for you and your family.

Timeline

DateEvent
The flaw is made public in the National Vulnerability Database, with a severity score of 5.8.[2]
CISA adds it to its catalog of flaws known to be used in attacks.[1]
CISA’s deadline for US government agencies to fix it.[1]
FIRST puts the odds of it being used in attacks in the next 30 days at 1%.[4]

See also

Other Arista flaws

  • CVE-2026-114625, Arista VeloCloud Orchestrator: SQL injection ·
  • CVE-2026-93952, Arista VeloCloud Orchestrator: improper input validation ·
  • CVE-2026-16812, Arista VeloCloud Orchestrator: on-prem OS command injection ·

Added the same day

  • CVE-2026-20245, Cisco Catalyst SD-WAN Manager: improper encoding or escaping of output ·
  • CVE-2026-11645, Chrome and other Chromium browsers: out-of-bounds read and write ·

Every Arista flaw on CISA’s list · Everything added in June 2026

References

  1. ^ Cybersecurity and Infrastructure Security Agency. “Arista Extensible Operating System Incomplete Comparison with Missing Factors Vulnerability”. Known Exploited Vulnerabilities Catalog, added 9 Jun 2026.
  2. ^ National Institute of Standards and Technology. “CVE-2026-7473 Detail”. National Vulnerability Database, published 5 Jun 2026.
  3. ^ Arista. Advisories and fixes: arista.com.
  4. ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.011, percentile 65.9, 31 Oct 2026.
  5. CVE Program. “CVE-2026-7473”. The official CVE record.

This article is built from CISA’s catalog (version 2026.10.30), NVD’s record and FIRST’s scores, kept in HARD’s database and checked every morning. The plain English is HARD’s.