On Arista EOS platforms running versions 4.27.2F, 4.28.0, 4.29.0, 4.30.0, 4.31.0, and 4.32.0, when MACsec and egress ACLs are configured simultaneously on the same interfaces, the egress ACL policies may fail to be enforced. This results in improper access control (CWE-284), potentially allowing or denying outgoing packets incorrectly. The vulnerability has a CVSS 4.0 base score of 6.9, indicating a medium severity level. No official patch or remediation guidance is currently provided by the vendor, and no known exploits are reported in the wild.

The vulnerability can cause egress ACL policies to be bypassed or incorrectly applied, leading to potential unauthorized network traffic flow or unintended blocking of legitimate traffic. This may affect network security posture by undermining intended access control policies on affected interfaces.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, administrators should review configurations involving MACsec and egress ACLs on the same interfaces and consider temporary workarounds such as disabling one of these features on the same interface if feasible. Monitor vendor communications for updates on patches or official mitigations.