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 ...
02 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 t ...
03 Exploitation and scoring
- Exploitation
- Assessed, none found. CISA's assessment recorded neither public exploit code nor evidence of exploitation when it was made.
- SSVC decision
- ExploitationnoneCISA recorded no public exploit code and no evidence of exploitation.
- AutomatableyesAn attacker can reliably automate reconnaissance through exploitation, so this scales.
- Technical ImpactpartialSuccessful exploitation gives limited control of the vulnerable component.
- EPSS probability
- 0.59% probability of exploitation activity in the next 30 days.
- EPSS percentile
- Equal to or higher than the score of 48.4% of scored records. A rank, not a probability.
- NVD base score
- 6.5 (CVSS v3.x), scored by the NVD independently of the CNA.
- NVD CVSS vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
- NVD analysis status
- Modified. NVD last modified this record on 2026-06-17.
- Red Hat severity
- No Red Hat rating. Red Hat rates the CVEs that affect its products.
Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.
04 Metadata
- Published
- 2022-08-05 16:47Z4 YR AGO
- Last updated
- 2026-06-02 14:07Z4 MO AGO
- Reserved
- 2021-03-16
- Assigning CNA
- Arista
- Record state
- PUBLISHED
- Severity
- Medium (CVSS 5.8)
- CNA CVSS vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
- Weaknesses
- CWE-284Improper Access ControlPillar
- Data version
- 5.2
- Document digest
- 595c5690a0b01871c1c572bdb03859d61edc74b392ae8356e0c8199c45000ac4
05 Affected products
06 References
07 Remediation
The recommended resolution is to upgrade to a remediated software version at your earliest convenience. The fixed versions for the currently supported release trains are as follows: 4.24.10 and later releases in the 4.24.x train 4.25.9 and later releases in the 4.25.x train 4.26.6 and later releases in the 4.26.x train 4.27.4 and later releases in the 4.27.x train 4.28.0 and later releases in the 4.28.x train