CVE-2021-28511
mediumpriority · track · 26EPSS 0.006 · 48 %ileEUUSEPSS · scored 2026-10-27
This advisory documents the impact of an internally found vulnerability in Arista EOS for security ACL bypass. The impact of this vulnerability is that the security ACL drop rule might be bypassed if a NAT ACL rule filter with permit action matches the packet flow. This could allow a host with an IP address in a range that matches the range allowed by a NAT ACL and a range denied by a Security ACL to be forwarded incorrectly as it should have been denied by the Security ACL. This can enable an ACL bypass.
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (8)
Products and version ranges known to be affected.
also known as (3)
Other names and identifiers for this entity.
sources
Which sources assert this record, and when.
references (4)
External citations — patches, advisories, analysis.
- https://cxsecurity.com/cveshow/CVE-2021-28511/cnnvd
- https://www.arista.com/en/support/advisories-notices/security-advisory/15862-security-advisory-0078cnnvd
- https://www.arista.com/en/support/advisories-notices/security-advisory/15862-security-advisory-0078enisa_euvd
- https://www.arista.com/en/support/advisories-notices/security-advisory/15862-security-advisory-0078ExploitMitigationVendor Advisorynvd
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