Description
On affected platforms running Arista EOS with dual switch cards and with ingress Security ACLs configured on Switched Virtual Interfaces (SVI) in shared mode, restarting of the secondary switchcard forwarding agent or insertion of secondary switchcard, can cause security ACLs on shared SVIs to stop functioning. This may result in incorrect packet permit/deny behavior.

This issue was discovered internally by Arista, and the company is not aware of any malicious exploitation of this vulnerability in customer networks.
Published: 2026-09-15
Score: 6.3 Medium
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

Vendor Solution

The recommended resolution is to upgrade to a remediated software version at your earliest convenience. Arista recommends customers move to the latest version of each release that contains all the fixes listed below. CVE-2026-73451 has been fixed in the following releases: * 4.36.1F and later releases in the 4.36.x train. * 4.35.5M and later releases in the 4.35.x train. * 4.34.7M and later releases in the 4.34.x train. * 4.33.9M and later releases in the 4.33.x train.

Vendor Workaround

The workaround is to re-configure (remove and reapply) the ingress IPv4 and IPv6 ACLs applied to all SVIs. For every SVI check the active ACL(s) applied to it, switch(config)# interface VlanNNN switch(config-if-VlNNN)# show active   Then remove the ACL(s) and re-apply them, switch(config-if-VlNNN)# no ip access-group <acl name> in switch(config-if-VlNNN)# ip access-group <acl name> in switch(config-if-VlNNN)# no ipv6 access-group <acl name> in switch(config-if-VlNNN)# ipv6 access-group <acl name> in   Note: the security provided by the ACL configuration will not be present during the removal/reapplication of the security ACLs. For more information about Security ACLs see EOS User Manual: ACLs and Route Maps https://www.arista.com/en/um-eos/eos-acls-and-route-maps .

Tracking

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Advisories

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History

Tue, 15 Sep 2026 20:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Tue, 15 Sep 2026 18:30:00 +0000

Type Values Removed Values Added
Description On affected platforms running Arista EOS with dual switch cards and with ingress Security ACLs configured on Switched Virtual Interfaces (SVI) in shared mode, restarting of the secondary switchcard forwarding agent or insertion of secondary switchcard, can cause security ACLs on shared SVIs to stop functioning. This may result in incorrect packet permit/deny behavior. This issue was discovered internally by Arista, and the company is not aware of any malicious exploitation of this vulnerability in customer networks.
Title On affected platforms running Arista EOS with dual switch cards and with ingress Security ACLs configured on Switched Virtual Interfaces (SVI) in shared mode, restarting of the secondary switchcard forwarding agent or insertion of secondary switchcard, can
Weaknesses CWE-1419
References
Metrics cvssV3_1

{'score': 4.8, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N'}

cvssV4_0

{'score': 6.3, 'vector': 'CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N'}

Subscriptions

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cve-icon MITRE

Status: PUBLISHED

Assigner: Arista

Published:

Updated: 2026-09-15T19:24:42.924Z

Reserved: 2026-08-12T16:42:47.921Z

Link: CVE-2026-73451

cve-icon Vulnrichment

Updated: 2026-09-15T19:24:39.313Z

cve-icon NVD

Status : Received

Published: 2026-09-15T19:17:38.960

Modified: 2026-09-15T20:17:42.610

Link: CVE-2026-73451

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses
  • CWE-1419

    Incorrect Initialization of Resource