How severe is CVE-2021-28494?

CVE-2021-28494 has a CVSS 3.x base score of 9.6, rated critical severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability high.

Is CVE-2021-28494 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-2021-28494?

CVE-2021-28494 affects Arista Metamako Operating System. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-28494?

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

When was CVE-2021-28494 published?

CVE-2021-28494 was published on 2021-09-09 and last updated on 2026-06-17.

CVE-2021-28494

CVE-2021-28494 is a critical-severity vulnerability in Arista Metamako Operating System with a CVSS 3.x base score of 9.6. 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: Critical (CVSS 3.x base score 9.6)
CVSS v2: 6.5
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, authentication is bypassed by unprivileged users who are accessing the Web UI. This issue affects: Arista Metamako Operating System MOS-0.34.0 and prior releases

Frequently asked questions

What is CVE-2021-28494?: In Arista's MOS (Metamako Operating System) software which is supported on the 7130 product line, under certain conditions, authentication is bypassed by unprivileged users who are accessing the Web UI. This issue affects: Arista Metamako Operating System MOS-0.34.0 and prior releases
How severe is CVE-2021-28494?: CVE-2021-28494 has a CVSS 3.x base score of 9.6, rated critical severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability high.
Is CVE-2021-28494 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-2021-28494?: CVE-2021-28494 affects Arista Metamako Operating System. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-28494?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2021-28494 published?: CVE-2021-28494 was published on 2021-09-09 and last updated on 2026-06-17.

References

https://www.arista.com/en/support/advisories-notices/security-advisories/12916-security-advisory-68

Affected products (1)

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

More vulnerabilities in Arista Metamako Operating System

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-2021-28495 — High (CVSS 7.2): 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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