In Arista’s EOS when in 802.1X mode, multi-auth unauthenticated hosts might be allowed access to a switch port if there exists an EAPOL capable device in the fallback VLAN.

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Fixes

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. For more information about upgrading see  EOS User Manual: Upgrades and Downgrades https://www.arista.com/en/um-eos/eos-upgrades-and-downgrades CVE-2024-6858 has been fixed in the following releases: * 4.31.2F and later releases in the 4.31.x train. * 4.30.6M and later releases in the 4.30.x train. * 4.29.8M and later releases in the 4.29.x train. * 4.28.11M and later releases in the 4.28.x train.


Workaround

This vulnerability arises when there is an EAPOL supplicant in any of the fallback VLAN’s ( i.e. auth-fail, unresponsive VLAN ). If only unauthenticated EAPOL supplicants are expected the admin can change dot1x host-mode to single-host as indicated below. switch(config-if-et1)#dot1x host-mode single-host * Dot1x Host Mode * Single Host Mode: Please note when once the 802.1X supplicant is authenticated on the port, ONLY the traffic coming from the supplicant's MAC is allowed through the port. * Multi-Host Mode: Once the 802.1X supplicant is authenticated on the port, traffic coming from ANY source MAC is allowed through the port. * Multi-Host authenticated Mode: Multiple 802.1X supplicants can be allowed and ONLY the traffic coming from all authenticated supplicant’s MAC is allowed through the port.

History

Fri, 05 Jun 2026 10:45:00 +0000

Type Values Removed Values Added
First Time appeared Arista
Arista eos
Vendors & Products Arista
Arista eos

Thu, 04 Jun 2026 22:15:00 +0000

Type Values Removed Values Added
Description In Arista’s EOS when in 802.1X mode, multi-auth unauthenticated hosts might be allowed access to a switch port if there exists an EAPOL capable device in the fallback VLAN.
Title In Arista’s EOS when in 802.1X mode, multi-auth unauthenticated hosts might be allowed access to a switch port if there exists an EAPOL capable device in the fallback VLAN.
Weaknesses CWE-1287
References

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cve-icon MITRE

Status: PUBLISHED

Assigner: Arista

Published:

Updated: 2026-06-04T21:51:08.709Z

Reserved: 2024-07-17T20:13:57.799Z

Link: CVE-2024-6858

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-06-04T22:16:51.843

Modified: 2026-06-04T22:16:51.843

Link: CVE-2024-6858

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-06-05T10:07:20Z

Weaknesses