What’s Vulnerable › Vulnerabilities

CVE-2021-28505: On affected Arista EOS platforms, if a VXLAN match rule exists in an IPv4 access-list that is applied to the ingress of an L2 or an L3 port/SVI, the VXLAN rule and subsequent ACL rules in that access list will ignore the specified IP protocol.

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.9% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2022-04-14 · updated 2026-06-17
• Weakness: CWE-284

Description

On affected Arista EOS platforms, if a VXLAN match rule exists in an IPv4 access-list that is applied to the ingress of an L2 or an L3 port/SVI, the VXLAN rule and subsequent ACL rules in that access list will ignore the specified IP protocol.

Affected products

• Arista Networks EOS: from 4.26 before 4.26.4m; from 4.27 before 4.27.1f — fixed in 4.26.4m, 4.27.1f

How to fix

Upgrade to a fixed version: Arista Networks EOS 4.26.4m, 4.27.1f. Check the vendor advisory for mitigations.

References

• https://www.arista.com/en/support/advisories-notices/security-advisories/15267-security-advisory-0073
• https://www.arista.com/en/support/advisories-notices/security-advisories/15267-security-advisory-0073

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