Medium severity · published Aug 5, 2022
CVE-2021-28511
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 t ...
6.5
CVSS
0.6%
EPSS
No
On KEV
Description
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 vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
Low
Integrity
Low
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.6% · higher than 48% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
EO
EOS · Arista Networks
4.24.0 through 4.24.9; 4.25.0 through 4.25.8; 4.26.0 through 4.26.5; 4.27.0 through 4.27.3 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-28511
CVE.org
https://www.cve.org/CVERecord?id=CVE-2021-28511
Exploit
https://www.arista.com/en/support/advisories-notices/security-advisory/15862-security-advisory-0078
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