CVE-2020-26569

Name: CVE-2020-26569
Creator: NVD / NIST
Published: 2020-12-28T16:15:12.87+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 5.9/10EPSS 0.84%

Last modified Jun 17, 2026

CVE-2020-26569 is a medium-severity vulnerability rated 5.9/10 on the CVSS scale. In EVPN VxLAN setups in Arista EOS, specific malformed packets can lead to incorrect MAC to IP bindings and as a result packets can be incorrectly forwarded across VLAN boundaries. This can result in traffic being discarded on the receiving VLAN. EPSS estimates a 0.84% chance of exploitation in the next 30 days.

Description

In EVPN VxLAN setups in Arista EOS, specific malformed packets can lead to incorrect MAC to IP bindings and as a result packets can be incorrectly forwarded across VLAN boundaries. This can result in traffic being discarded on the receiving VLAN. This affects versions: 4.21.12M and below releases in the 4.21.x train; 4.22.7M and below releases in the 4.22.x train; 4.23.5M and below releases in the 4.23.x train; 4.24.2F and below releases in the 4.24.x train.

Metrics

CVSS 3.1

5.9/10

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Probability

0.84%

53.2th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Vendor	Product	Versions
Arista	Eos	>= 4.21.0f, <= 4.21.12m
Arista	Eos	>= 4.22.0f, <= 4.22.7m
Arista	Eos	>= 4.23.0f, <= 4.23.5m
Arista	Eos	>= 4.24.0f, <= 4.24.2f

References

https://www.arista.com/en/support/advisories-notices/security-advisories/11997-security-advisory-57Exploit, Vendor Advisory
https://www.arista.com/en/support/advisories-notices/security-advisories/11997-security-advisory-57Exploit, Vendor Advisory

Timeline

Published: Dec 28, 2020
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-26569?

How severe is CVE-2020-26569?

CVE-2020-26569 has a CVSS score of 5.9/10 (MEDIUM severity). The EPSS model estimates a 0.84% probability of exploitation in the next 30 days.

How do I fix CVE-2020-26569?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2020-26569?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST