CVE-2021-28501Network attack vector

Unauthenticated access via AAA authorization bypass

Published Jan 14, 2022 · Updated Sep 17, 2024

Authentication bypass in Arista TerminAttr 1.16.1 and earlier allows remote attackers to gain unrestricted device access via gNMI. TerminAttr incorrectly uses EOS AAA APIs, so gNMI requests bypass authorization when no-password remote login is allowed and a local nopassword account exists. The condition requires TerminAttr gNMI to be enabled; mutual TLS can prevent the authentication exposure, and the reported impact is device integrity and availability rather than data disclosure.

CVSS severity9.1
Critical
EPSS probability0.84%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in Arista TerminAttr 1.16.1 and earlier allows remote attackers to gain unrestricted device access via gNMI. TerminAttr incorrectly uses EOS AAA APIs, so gNMI requests bypass authorization when no-password remote login is allowed and a local nopassword account exists. The condition requires TerminAttr gNMI to be enabled; mutual TLS can prevent the authentication exposure, and the reported impact is device integrity and availability rather than data disclosure.

The record

CVE
CVE-2021-28501
Published
Jan 14, 2022
Updated
Sep 17, 2024
Vendor
Arista Networks
Product
TerminAttr
Classifications
CWE-285, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 14, 2022CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1.16.2 0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Arista Networks · TerminAttrversion=1.16.2 0

Published CVSS scores

6.9NVDAV:L/AC:M/Au:N/C:C/I:C/A:C
7.8NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
9.1Arista NetworksCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-285Improper Authorization
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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