CVE-2024-27891

On affected platforms running Arista EOS with MACsec and egress ACLs configured on the same interfaces, the ACL policies may not be enforced for packets egressing on those ports.

MEDIUM
5.3
CVSS Score
Published: June 4, 2026 at 10:08 PM UTC
Updated: July 22, 2026 at 08:24 PM UTC
1 product affected across 1 vendorArista EOS

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Severity
MEDIUM5.3
Exploit prediction
EPSS 0.3%
SSVC
No known exploit

Description

On affected platforms running Arista EOS with MACsec and egress ACLs configured on the same interfaces, the ACL policies may not be enforced for packets egressing on those ports. This can cause outgoing packets to incorrectly be allowed or denied.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

4.27.2F ≤ v < 4.28.04.28.0 ≤ v ≤ 4.28.10.1M4.29.0 ≤ v ≤ 4.29.7M4.30.0 ≤ v ≤ 4.30.6M4.31.0 ≤ v ≤ 4.31.2F4.32.0 ≤ v ≤ 4.32.0.1F4.27.2F4.28.04.29.04.30.04.31.04.32.0
Affected range stops below 4.28.0, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.3MEDIUMArista
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
LOW
Availability
NONE
Vector?

Quick Info

StatusAWAITING ANALYSIS
CWE
CWE-284

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