How severe is CVE-2021-28503?

CVE-2021-28503 has a CVSS 3.x base score of 7.4, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability high.

Is CVE-2021-28503 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (50th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-28503?

CVE-2021-28503 affects Arista Eos. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-28503?

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-2021-28503 published?

CVE-2021-28503 was published on 2022-02-04 and last updated on 2026-06-17.

CVE-2021-28503

CVE-2021-28503 is a high-severity vulnerability in Arista Eos with a CVSS 3.x base score of 7.4. 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 7.4)
CVSS v2: 6.8
EPSS exploit prediction: 1% (50th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-287
Affected product: Arista Eos
Published: 2022-02-04
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2021-28503?: 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.
How severe is CVE-2021-28503?: CVE-2021-28503 has a CVSS 3.x base score of 7.4, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability high.
Is CVE-2021-28503 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (50th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-28503?: CVE-2021-28503 affects Arista Eos. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-28503?: 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-2021-28503 published?: CVE-2021-28503 was published on 2022-02-04 and last updated on 2026-06-17.

References

https://www.arista.com/en/support/advisories-notices/security-advisories/13605-security-advisory-0072

Affected products (1)

cpe:2.3:o:arista:eos:*:*:*:*:*:*:*:*

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Other CWE-287 (Improper Authentication) vulnerabilities

CVE-2026-45480 — Critical (CVSS 10.0): Improper authentication in Azure Active Directory allows an unauthorized attacker to elevate privileges over a network.
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CVE-2026-10611 — Critical (CVSS 10.0): An authentication bypass vulnerability exists in MISP when LDAP mixed authentication is enabled with OTP enforcement.…
CVE-2026-47280 — Critical (CVSS 10.0): Improper authentication in Azure Resource Manager (ARM) allows an unauthorized attacker to elevate privileges over a…
CVE-2026-42822 — Critical (CVSS 10.0): Improper authentication in Azure Local Disconnected Operations allows an unauthorized attacker to elevate privileges…
CVE-2026-20182 — Critical (CVSS 10.0): May 2026: This security advisory provides the details and fix information for a vulnerability that was discovered and…

Browse all CWE-287 (Improper Authentication) vulnerabilities →