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TI-2021-09618 Aliases CVE-2021-28511GHSA-7rjh-m68p-34pq

Improper access control in Arista EOS

Priority LOW 36CWE-284Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Security bypass
Confidentiality · integrity · availability
Low · Low · None
Fix status
No fix listed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA. Impact type from CWE-284.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00597 48th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
AristaEOS4.24.0 – 4.24.9; 4.25.0 – 4.25.8; 4.26.0 – 4.26.5; 4.27.0 – 4.27.3—No fix listedCNA
  • EOS VendorArista Affected 4.24.0 – 4.24.9; 4.25.0 – 4.25.8; 4.26.0 – 4.26.5; 4.27.0 – 4.27.3 Fixed in — No fix listed CNA

CPE configurations NVD · 16

CPEVersionsRoleVendor
cpe:2.3:o:arista:eos:*:*:*:*:*:*:*:*up to 4.24.9; 4.25.0 – 4.25.8; 4.26.0 – 4.26.5; 4.27.0 – 4.27.3VulnerableArista
cpe:2.3:h:arista:7050cx3-32s:-:*:*:*:*:*:*:*not specified by NVDRunning onArista
cpe:2.3:h:arista:7050cx3m-32s:-:*:*:*:*:*:*:*not specified by NVDRunning onArista
cpe:2.3:h:arista:7050sx3-48c8:-:*:*:*:*:*:*:*not specified by NVDRunning onArista
cpe:2.3:h:arista:7050sx3-48yc:-:*:*:*:*:*:*:*not specified by NVDRunning onArista
cpe:2.3:h:arista:7050sx3-48yc12:-:*:*:*:*:*:*:*not specified by NVDRunning onArista
cpe:2.3:h:arista:7050sx3-48yc8:-:*:*:*:*:*:*:*not specified by NVDRunning onArista
cpe:2.3:h:arista:7050sx3-96yc8:-:*:*:*:*:*:*:*not specified by NVDRunning onArista
cpe:2.3:h:arista:7050tx3-48c8:-:*:*:*:*:*:*:*not specified by NVDRunning onArista
cpe:2.3:h:arista:720xp-24y6:-:*:*:*:*:*:*:*not specified by NVDRunning onArista
  • cpe:2.3:o:arista:eos:*:*:*:*:*:*:*:* Versions up to 4.24.9; 4.25.0 – 4.25.8; 4.26.0 – 4.26.5; 4.27.0 – 4.27.3 Vulnerable ·Arista
  • cpe:2.3:h:arista:7050cx3-32s:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Arista
  • cpe:2.3:h:arista:7050cx3m-32s:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Arista
  • cpe:2.3:h:arista:7050sx3-48c8:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Arista
  • cpe:2.3:h:arista:7050sx3-48yc:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Arista
  • cpe:2.3:h:arista:7050sx3-48yc12:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Arista
  • cpe:2.3:h:arista:7050sx3-48yc8:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Arista
  • cpe:2.3:h:arista:7050sx3-96yc8:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Arista
  • cpe:2.3:h:arista:7050tx3-48c8:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Arista
  • cpe:2.3:h:arista:720xp-24y6:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Arista
Show 6 more CPE
CPEVersionsRoleVendor
cpe:2.3:h:arista:720xp-24zy4:-:*:*:*:*:*:*:*not specified by NVDRunning onArista
cpe:2.3:h:arista:720xp-48y6:-:*:*:*:*:*:*:*not specified by NVDRunning onArista
cpe:2.3:h:arista:720xp-48zc2:-:*:*:*:*:*:*:*not specified by NVDRunning onArista
cpe:2.3:h:arista:720xp-96zc2:-:*:*:*:*:*:*:*not specified by NVDRunning onArista
cpe:2.3:h:arista:7300x3-32c:-:*:*:*:*:*:*:*not specified by NVDRunning onArista
cpe:2.3:h:arista:7300x3-48yc4:-:*:*:*:*:*:*:*not specified by NVDRunning onArista
  • cpe:2.3:h:arista:720xp-24zy4:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Arista
  • cpe:2.3:h:arista:720xp-48y6:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Arista
  • cpe:2.3:h:arista:720xp-48zc2:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Arista
  • cpe:2.3:h:arista:720xp-96zc2:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Arista
  • cpe:2.3:h:arista:7300x3-32c:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Arista
  • cpe:2.3:h:arista:7300x3-48yc4:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Arista

Remediation

No fixed version listed by the sources yet.

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-28511
  2. 2026-10-03 Alias added: GHSA-7rjh-m68p-34pq

References

Exploit 1

  • TI-2014-05975 GNU Bash through 4.3 bash43-025 processes trailing strings after certain malformed… KEVCVSS 3.1CRITICAL 9.8
  • TI-2014-05157 GNU Bash through 4.3 processes trailing strings after function definitions in the values… KEVCVSS 3.1CRITICAL 9.8
  • TI-2026-06569 Arista EOS Unexpected Tunnel Protocol Decapsulation and Forwarding Bypass KEVCVSS 4.0MEDIUM 6.9
  • TI-2017-10594 Heap-based buffer overflow in dnsmasq before 2.78 allows remote attackers to cause a… CVSS 3.1CRITICAL 9.8
  • TI-2024-05929 Openssh: regresshion - race condition in ssh allows rce/dos CVSS 3.1HIGH 8.1
  • TI-2020-08209 utility.c in telnetd in netkit telnet through 0.17 allows remote attackers to execute… CVSS 3.1CRITICAL 9.8
See all 45 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences