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CVE-2021-28503

In Arista's EOS software affected releases, eAPI might skip re-evaluating user credentials when certificate based authentication is used, which allows remote attackers to access the device via eAPI.

High7.4EPSS 0.73%
Published
Updated
Reserved
Assigned by
Arista

Description

The impact of this vulnerability is that Arista's EOS eAPI may skip re-evaluating user credentials when certificate based authentication is used, which allows remote attackers to access the device via eAPI.

Timeline

  1. ID reserved

    By Arista

  2. · 11 months later

    Published

  3. · 3 years later

    Record updated

Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.

Scores

CVSS scores of CVE-2021-28503, by who scored it
Scored byCVSSScoreVector
AristaCNA (assigner)3.1High7.4CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H
NVDNVD · Modified3.1Critical9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS (exploitation in 30 days)
0.73% · top 45% of all CVEs (7 Nov 2026)
Loading the EPSS history…

The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.4.

Weakness

Affected products

  • Arista Networks · Arista EOS

    • affected EOS-4.23 – < EOS-4.23.10
    • affected EOS-4.24 – < EOS-4.24.8
    • affected EOS-4.25 – < EOS-4.25.6
    • affected EOS-4.26 – < EOS-4.26.3

What to do

Solution: The recommended resolution is to upgrade to a remediated software version at your earliest convenience. The vulnerability is fixed in the following EOS versions: 4.26.3 and later releases in the 4.26.x train 4.25.6 and later releases in the 4.25.x train 4.24.8 and later releases in the 4.24.x train 4.23.10 and later releases in the 4.24.x train

Workaround: Disallowing user certificate authentication via eAPI can be used to mitigate the vulnerability. switch(config)#management security switch(config-mgmt-security)#ssl profile profileEAPI switch(config-mgmt-sec-ssl-profile-profileEAPI)#no trust certificate user.cert switch(config-mgmt-sec-ssl-profile-profileEAPI)#exit

References (1)

Sources

The same CVE in the primary databases and aggregators, to check against.

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Record last updated .