CVE detail

CVE-2021-28505 — CVE-2021-28505

Published 2022-04-14 · Modified 2026-06-17 · Vendor arista · Product eos · Source nvd

HIGH

severity

CVSS-derived band

7.5

CVSS v3

0–10 scale

0.0087

EPSS probability

exploitation probability, 30d

55.0%

EPSS percentile

percentile vs all CVEs

NOT LISTED

CISA KEV

known exploited catalog

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.

Remediation

vendor remediation guidance

The recommended resolution is to upgrade to a remediated software version at your earliest convenience. Artista recommends customers move to the latest version of each release that contains all the fixes listed below. CVE-2021-28505 has been fixed in the following releases: 4.26.4M and later releases in the 4.26.x train 4.27.1F and later releases in the 4.27.x train

workarounds

Replace "vxlan" IP protocol match with match on IP protocol "udp" and Layer 4 destination port for VxLAN encapsulated packets i.e 4789. < br/> If VXLAN L4 destination port number is not the default 4789 then use the configured L4 destination port number.

Product	Vulnerable range	Fixed version	Advisory
Arista Networks EOS	>=4.26.3M<=4.26.0	4.26.0	advisory ↗
Arista Networks EOS	>=4.27.0F<=4.27.0	4.27.0	advisory ↗

References

cvedb.io · NVD · CISA KEV · FIRST EPSS · vendor advisories (CVE Program List v5). Informational only, no warranty — verify every remediation against the vendor advisory before acting on it. This product uses data from the NVD API but is not endorsed or certified by the NVD, CISA, FIRST.org or any vendor named. CVE® is a registered trademark of The MITRE Corporation.