How severe is CVE-2021-28495?

CVE-2021-28495 has a CVSS 3.x base score of 7.2, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability low.

Is CVE-2021-28495 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (56th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-28495?

CVE-2021-28495 affects Arista Metamako Operating System. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-28495?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-28495 published?

CVE-2021-28495 was published on 2021-09-09 and last updated on 2026-06-17.

CVE-2021-28495

CVE-2021-28495 is a high-severity vulnerability in Arista Metamako Operating System with a CVSS 3.x base score of 7.2. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-287.

Key facts

Severity: High (CVSS 3.x base score 7.2)
CVSS v2: 6.8
EPSS exploit prediction: 1% (56th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-287
Affected product: Arista Metamako Operating System
Published: 2021-09-09
Last modified: 2026-06-17

Description

In Arista's MOS (Metamako Operating System) software which is supported on the 7130 product line, under certain conditions, user authentication can be bypassed when API access is enabled via the JSON-RPC APIs. This issue affects: Arista Metamako Operating System All releases in the MOS-0.1x train MOS-0.13 and post releases in the MOS-0.1x train MOS-0.26.6 and below releases in the MOS-0.2x train MOS-0.31.1 and below releases in the MOS-0.3x train

Frequently asked questions

What is CVE-2021-28495?: In Arista's MOS (Metamako Operating System) software which is supported on the 7130 product line, under certain conditions, user authentication can be bypassed when API access is enabled via the JSON-RPC APIs. This issue affects: Arista Metamako Operating System All releases in the MOS-0.1x train MOS-0.13 and post releases in the MOS-0.1x train MOS-0.26.6 and below releases in the MOS-0.2x train MOS-0.31.1 and below releases in the MOS-0.3x train
How severe is CVE-2021-28495?: CVE-2021-28495 has a CVSS 3.x base score of 7.2, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability low.
Is CVE-2021-28495 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (56th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-28495?: CVE-2021-28495 affects Arista Metamako Operating System. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-28495?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-28495 published?: CVE-2021-28495 was published on 2021-09-09 and last updated on 2026-06-17.

References

https://www.arista.com/en/support/advisories-notices/security-advisories/12914-security-advisory-66

Affected products (1)

cpe:2.3:o:arista:metamako_operating_system:*:*:*:*:*:*:*:*

More vulnerabilities in Arista Metamako Operating System

CVE-2021-28494 — Critical (CVSS 9.6): In Arista's MOS (Metamako Operating System) software which is supported on the 7130 product line, under certain…
CVE-2021-28498 — High (CVSS 8.7): In Arista's MOS (Metamako Operating System) software which is supported on the 7130 product line, user enable passwords…
CVE-2021-28493 — High (CVSS 8.4): In Arista's MOS (Metamako Operating System) software which is supported on the 7130 product line, under certain…
CVE-2021-28499 — Medium (CVSS 6.3): In Arista's MOS (Metamako Operating System) software which is supported on the 7130 product line, user account…
CVE-2021-28497 — Medium (CVSS 4.4): In Arista's MOS (Metamako Operating System) software which is supported on the 7130 product line, under certain…

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