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Fencer Vulns
medium 5.9

CVE-2020-26569 json

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 inco…

published 2020-12-28 5 y ago modified 2026-06-17 4 mo ago also EUVD-2020-19114

cvss
5.9
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.9%
EPSS 0.9% chance of exploitation in 30 days, percentile 58%
public exploits
0
none known

Summary

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.

Exploit prediction

0.85% chance of exploitation in the next 30 days, higher than 58% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • arista.com https://www.arista.com/en/support/advisories-notices/security-advisories/11997-security-advisory-57 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:N/I:N/A:P

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.