CVE-2026-73451Network attack vector

ACL bypass via switch-card forwarding-agent reinitialization

Published Sep 15, 2026 · Updated Sep 15, 2026

Incorrect resource initialization in Arista EOS allows remote attackers to bypass ingress ACL filtering on shared SVIs after a switch-card event. Restarting the secondary switch-card forwarding agent or inserting the card leaves shared-mode SVI ingress ACLs nonfunctional, producing incorrect permit and deny decisions. Exposure requires a 755 or 758 Series chassis with dual switch cards and a security ACL applied inbound to an SVI using the default shared ACL identifier.

CVSS severity4.8
Medium
EPSS probability0.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Incorrect resource initialization in Arista EOS allows remote attackers to bypass ingress ACL filtering on shared SVIs after a switch-card event. Restarting the secondary switch-card forwarding agent or inserting the card leaves shared-mode SVI ingress ACLs nonfunctional, producing incorrect permit and deny decisions. Exposure requires a 755 or 758 Series chassis with dual switch cards and a security ACL applied inbound to an SVI using the default shared ACL identifier.

The record

CVE
CVE-2026-73451
Published
Sep 15, 2026
Updated
Sep 15, 2026
Vendor
Arista Networks
Product
Arista EOS
Classifications
CWE-1419, T1599
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 15, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 15, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=4.31.1F <=4.31.10M
  2. Affected versionversion=4.32.0 <=4.32.11M
  3. Affected versionversion=4.33.0 <=4.33.8M
  4. Affected versionversion=4.34.0 <=4.34.6M
  5. Affected versionversion=4.35.0 <=4.35.4M
  6. Affected versionversion=4.36.0 <=4.36.0.1F

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Arista Networks · Arista EOSversion=4.31.1F <=4.31.10M; version=4.32.0 <=4.32.11M; version=4.33.0 <=4.33.8M; version=4.34.0 <=4.34.6M; version=4.35.0 <=4.35.4M; version=4.36.0 <=4.36.0.1F

Published CVSS scores

6.3Arista NetworksCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N
4.8Arista NetworksCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-1419Incorrect Initialization of Resource
T1599Network Boundary Bridging

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo