major vulnerability· requires attention

Unauthenticated RCE in Arista EOS switches can give full control of network infrastructure used widely in enterprises and data centers.

Networks

CVE-2026-73456

9.2

Critical

EPSS 0.69%Patch available

Unauthenticated RCE in Arista EOS gNPSI allows full administrative takeover of switches.

exploited

No known exploitation not in CISA KEV as of our last sync

fix

Patch available see the advisory in the references

likelihood

EPSS 0.69%top 48% of scored CVEs

Published 16 Sept 2026Analysed here 18 Sept 2026CVSS scored by the publisher (CNA)

common questions

Is CVE-2026-73456 being exploited?

Not confirmed. CVE-2026-73456 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.69% probability of exploitation in the next 30 days.

How severe is CVE-2026-73456?

CVE-2026-73456 is rated Critical with a CVSS score of 9.2. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.

Is there a patch for CVE-2026-73456?

Yes. A fix has been recorded for CVE-2026-73456. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.

What does CVE-2026-73456 affect?

CVE-2026-73456 affects Arista EOS switches with gNPSI (Network Packet Sampling) enabled. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.

What should I do about CVE-2026-73456?

Isolate/segment management plane, disable gNPSI, apply vendor updates from advisory when available

Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.

executive summary

technical analysis

affected

Arista EOS switches with gNPSI (Network Packet Sampling) enabled

impact

Unauthenticated remote code execution via gNPSI request, granting full administrative control of affected switches and network disruption.

action required

Immediate action required

affected versions

Arista Networks EOS

affected>= 4.36.0 and <= 4.36.1F
affected>= 4.35.0 and <= 4.35.5M
affected>= 4.34.2F and <= 4.34.7M

As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.

cisa ssvc

exploitation: none
automatable: yes
technical impact: total

Assessed by CISA 17 Sept 2026 (SSVC 2.0.3).

timeline

16 Sept 2026Published
17 Sept 2026CISA SSVC assessment: exploitation none · same day later
17 Sept 2026CVE record last updated · same day later
18 Sept 2026Analysed by vulneraibility.com · 1 day later

how to fix

Remediation steps are tailored for users whose stack is affected. Add this technology to your stack to see the fix checklist.

references

NVD CVE.org CVE Details Source

1 reference in the CVE record: 1 advisory

Advisoryarista.com /en/support/advisories-notices/security-advisory/24714-security-advisory-0158

sources

CVE List (CVE.org): description, affected versions, references; CVE Terms of Use
NVD: CVSS and CPE data
CISA Vulnrichment (ADP): SSVC decision points
FIRST EPSS: exploit probability and percentile
Summary, impact and triage tags: written by our AI analysis pipeline from the sources above. Check them against the sources.

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