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Full vulnerability report · 2026
CVE-2026-7473High confidence

Arista Extensible Operating System Incomplete Comparison with Missing Factors Vulnerability

Arista · Extensible Operating System

6.9MediumCVSS 4.0
Recommended action
Patch now

CISA confirms exploitation in the wild and lists 2026-06-23 as the remediation due date.

Patch available
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityMediumOperational priority:Critical, raised 2 bands.upgradedsince 9 Jun 2026

Evidence used

  • CISA confirms exploitation in the wild.
  • The selected CVSS metric records a network-reachable, unauthenticated path with no user interaction.
  • EPSS is 0.65% for the current model date.

Compensating controls

  • Validate the affected product branch and deploy the verified fixed release.
  • Restrict the affected network interface to trusted sources where business-safe.
  • Increase monitoring for the attack path and post-exploitation behaviour described in the report.

Verification

  1. Confirm that the asset runs Arista Extensible Operating System and falls inside the recorded affected range.
  2. Verify the installed build against the product-specific fixed version after deployment.
  3. Validate exposure, authentication requirements and compensating controls in the actual environment.
  4. Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Mitigation target: Within 3 daysRemediation target: Within 90 days

This automated reassessment organises public evidence. It does not know asset exposure, business impact or control effectiveness and does not replace CVSS or a human risk decision.

Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2026-34858

CISA KEV mirrored by ENISA

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.

EUVD state
Present in the current official mapping
Known exploitation
Recorded by ENISA since 9 Jun 2026. Evidence sources: cisa_kev.
ENISA score
6.9 · CVSS 4.0
Advisory evidence
No linked advisory details stored yet
Recommended actionPatch now

CISA confirms exploitation in the wild and lists 2026-06-23 as the remediation due date.

Patch available
01

What, why and how

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.

What

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.

Why

The product performs a comparison between entities that must consider multiple factors or characteristics of each entity, but the comparison does not include one or more of these factors.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

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.

Why

The product performs a comparison between entities that must consider multiple factors or characteristics of each entity, but the comparison does not include one or more of these factors.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
Confirmed in the wild

CISA added this CVE to its Known Exploited Vulnerabilities catalogue on 2026-06-09.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
a network path → Incomplete Comparison with Missing Factors → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Not a CVSS 4.0 base metric
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-1023 ↗

CWE-1023: Incomplete Comparison with Missing Factors. The product performs a comparison between entities that must consider multiple factors or characteristics of each entity, but the comparison does not include one or more of these factors.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
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

Common Vulnerability Scoring System 4.0: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.ATNoneAttack requirements: No additional deployment or execution condition is required.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.VCNoneVulnerable-system confidentiality: No direct loss is represented by this metric.VILowVulnerable-system integrity: A successful attack can cause a limited loss.VANoneVulnerable-system availability: No direct loss is represented by this metric.SCNoneSubsequent-system confidentiality: No direct loss is represented by this metric.SILowSubsequent-system integrity: A successful attack can cause a limited loss.SANoneSubsequent-system availability: No direct loss is represented by this metric.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
NetworkUnauthenticatedCWE-1023CISA KEV
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

ENISA EUVD · EUVD-2026-34858Known-exploited evidence recorded

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.

Official EUVD record ↗
BSI · German · WID-SEC-2026-1374Arista EOS: Schwachstelle ermöglicht Umgehen von Sicherheitsvorkehrungen

Ein entfernter, anonymer Angreifer kann eine Schwachstelle in Arista EOS ausnutzen, um Sicherheitsvorkehrungen zu umgehen.

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20260610Security Bulletin 10 Jun 2026

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 10 Jun 2026, published on 10 June 2026. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2026-018946Arista Networks, Inc.のArista EOSにおける要素の欠如による不完全な比較に関する脆弱性

影響を受けるプラットフォームでArista EOSを実行している場合、VXLAN（Virtual Extensible LAN）、decap-groups、またはGRE（Generic Routing Encapsulation）トンネルインターフェースなどのトンネルデカプセル化設定が存在すると、スイッチは設定されたデカプセル化IPに一致する宛先IPを持つ予期しない他のトンネル化パケットを誤ってデカプセル化して転送します。これは、スイッチがトンネルプロトコルの種類を検証しないために発生し、設定されていないトンネルトラフィックが予期せず処理される可能性があります。この問題は実際に攻撃に悪用されていることが報告されています。

Official advisory ↗
KISA KrCERT/CC · Korean · KNVD-6836美 CISA 발표 주요 Exploit 정보공유(Update. 2026-06-09)

Arista Extensible Operating System Incomplete Comparison with Missing Factors Vulnerability

Official advisory ↗
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Patch available
Affected
EOS: * ≤ 4.30, 4.36.0, 4.34.0 ≤ 4.34, 4.31.0 ≤ 4.31, 4.32.0 ≤ 4.32, 4.33.0 ≤ 4.33, 4.35.0 ≤ 4.35
Fixed
No software upgrade path is planned to address this issue due to the risk of breaking existing configuration on deployments. The recommended resolution of this issue is to follow the appropriate mitigation instructions detailed in the workaround block.
Action
Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
Workaround
A mitigation or workaround reference is available from the source linked below; validate it against the affected product and version.
04

Evidence and provenance

Published 5 Jun 2026 · Last source change 10 Jun 2026, 03:57 UTC · CWE-1023 · Incomplete Comparison with Missing Factors

CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2026-34858
Product sourceCISA KEV
Remediation sourceCVE/CNA references
CWE sourceCNA
NVD statusNVD enriched

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates ↗
  1. Vendor guidanceAuthoritative vendor guidance changed: added remediation: arista.com/22872-security-advisory-0137; removed remediation: arista.com/24005-security-advisory-0137.
    Before
    mitigation: arista.com/24005-security-advisory-0137 · remediation: arista.com/24005-security-advisory-0137
    After
    mitigation: arista.com/24005-security-advisory-0137 · remediation: arista.com/22872-security-advisory-0137
    arista.com ↗
  2. Affected versionsThe structured affected or fixed version information changed.
    Before
    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 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    After
    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 · Fixed: No software upgrade path is planned to address this issue due to the risk of breaking existing configuration on deployments. The recommended resolution of this issue is to follow the appropriate mitigation instructions detailed in the workaround block.
    CNA ↗
  3. Remediation statusRemediation status changed from Mitigation available to Patch available.
    Before
    Mitigation available
    After
    Patch available
    arista.com ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Added to CISA KEV
Fixed release or patch reference recorded
ENISA EUVD · EUVD-2026-34858↗CISA KEV record↗Mitigation reference↗CVE authority or vendor reference↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2026-7473 · cve.blacktree.nl