CVE-2024-27891: CWE-284 Improper Access Control in Arista Networks EOS
CVE-2024-27891 is a medium-severity vulnerability in Arista Networks EOS affecting versions 4. 27. 2F through 4. 32. 0. It involves improper access control where egress ACL policies may not be enforced on interfaces configured with both MACsec and egress ACLs. This can result in outgoing packets being incorrectly allowed or denied, potentially impacting network traffic filtering.
AI Analysis
Technical Summary
This vulnerability in Arista EOS occurs on platforms running MACsec and egress ACLs on the same interfaces. Due to improper access control (CWE-284), the ACL policies may fail to be enforced on egress packets, causing incorrect packet filtering behavior. The CVSS 4.0 base score is 6.9 (medium severity), indicating a network attack vector with low complexity and no privileges or user interaction required, but with limited impact on confidentiality and integrity. The affected versions include 4.27.2F through 4.32.0. No official remediation or patch information is currently provided by the vendor.
Potential Impact
The vulnerability can cause ACL policies to be bypassed or incorrectly applied on egress traffic, potentially allowing unauthorized packets to leave the network or blocking legitimate traffic. This undermines the intended network access controls and could affect network security posture. There are no known exploits in the wild at this time.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, administrators should carefully evaluate the use of MACsec and egress ACLs together on affected EOS versions and consider alternative configurations to avoid this issue.
CVE-2024-27891: CWE-284 Improper Access Control in Arista Networks EOS
Description
CVE-2024-27891 is a medium-severity vulnerability in Arista Networks EOS affecting versions 4. 27. 2F through 4. 32. 0. It involves improper access control where egress ACL policies may not be enforced on interfaces configured with both MACsec and egress ACLs. This can result in outgoing packets being incorrectly allowed or denied, potentially impacting network traffic filtering.
CVSS v4.0
Score 6.9medium
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability in Arista EOS occurs on platforms running MACsec and egress ACLs on the same interfaces. Due to improper access control (CWE-284), the ACL policies may fail to be enforced on egress packets, causing incorrect packet filtering behavior. The CVSS 4.0 base score is 6.9 (medium severity), indicating a network attack vector with low complexity and no privileges or user interaction required, but with limited impact on confidentiality and integrity. The affected versions include 4.27.2F through 4.32.0. No official remediation or patch information is currently provided by the vendor.
Potential Impact
The vulnerability can cause ACL policies to be bypassed or incorrectly applied on egress traffic, potentially allowing unauthorized packets to leave the network or blocking legitimate traffic. This undermines the intended network access controls and could affect network security posture. There are no known exploits in the wild at this time.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, administrators should carefully evaluate the use of MACsec and egress ACLs together on affected EOS versions and consider alternative configurations to avoid this issue.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- Arista
- Date Reserved
- 2024-02-26T18:06:32.161Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a2200c5e29bf47b50d9ecc6
Added to database: 6/4/2026, 10:48:37 PM
Last enriched: 6/4/2026, 11:04:23 PM
Last updated: 6/5/2026, 5:04:38 AM
Views: 6
Community Reviews
0 reviewsCrowdsource mitigation strategies, share intel context, and vote on the most helpful responses. Sign in to add your voice and help keep defenders ahead.
Want to contribute mitigation steps or threat intel context? Sign in or create an account to join the community discussion.
Actions
Updates to AI analysis require Pro Console access. Upgrade inside Console → Billing.
External Links
Need more coverage?
Upgrade to Pro Console for AI refresh and higher limits.
For incident response and remediation, OffSeq services can help resolve threats faster.
Latest Threats
Check if your credentials are on the dark web
Instant breach scanning across billions of leaked records. Free tier available.