« Back to list

CVE-2021-28494

Status: ModifiedHigh (8.8)—

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

CVSS

Exploitation probability (EPSS)

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

Affected technologies (1)

Arista — Metamako Operating System

CWEs

References

Raw JSON (NVD)

Show
{
  "id": "CVE-2021-28494",
  "cveTags": [],
  "metrics": {
    "cvssMetricV2": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "version": "2.0",
          "baseScore": 6.5,
          "accessVector": "NETWORK",
          "vectorString": "AV:N/AC:L/Au:S/C:P/I:P/A:P",
          "authentication": "SINGLE",
          "integrityImpact": "PARTIAL",
          "accessComplexity": "LOW",
          "availabilityImpact": "PARTIAL",
          "confidentialityImpact": "PARTIAL"
        },
        "acInsufInfo": false,
        "impactScore": 6.4,
        "baseSeverity": "MEDIUM",
        "obtainAllPrivilege": false,
        "exploitabilityScore": 8,
        "obtainUserPrivilege": false,
        "obtainOtherPrivilege": false,
        "userInteractionRequired": false
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "psirt@arista.com",
        "cvssData": {
          "scope": "CHANGED",
          "version": "3.1",
          "baseScore": 9.6,
          "attackVector": "NETWORK",
          "baseSeverity": "CRITICAL",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 5.8,
        "exploitabilityScore": 3.1
      },
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 8.8,
          "attackVector": "NETWORK",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 2.8
      }
    ]
  },
  "affected": [
    {
      "source": "psirt@arista.com",
      "affectedData": [
        {
          "vendor": "Arista",
          "product": "Metamako Operating System",
          "versions": [
            {
              "status": "affected",
              "version": "MOS-0.35.0",
              "lessThan": "MOS-0.35.0",
              "versionType": "custom"
            }
          ],
          "platforms": [
            "Arista 7130 Systems running MOS"
          ]
        }
      ]
    }
  ],
  "published": "2021-09-09T13:15:09.013",
  "references": [
    {
      "url": "https://www.arista.com/en/support/advisories-notices/security-advisories/12916-security-advisory-68",
      "tags": [
        "Mitigation",
        "Vendor Advisory"
      ],
      "source": "psirt@arista.com"
    },
    {
      "url": "https://www.arista.com/en/support/advisories-notices/security-advisories/12916-security-advisory-68",
      "tags": [
        "Mitigation",
        "Vendor Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    }
  ],
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "psirt@arista.com",
      "description": [
        {
          "lang": "en",
          "value": "CWE-287"
        }
      ]
    },
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "CWE-287"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "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"
    },
    {
      "lang": "es",
      "value": "En el software MOS (Sistema Operativo Metamako) de Arista, compatible con la línea de productos 7130, en determinadas condiciones, la autenticación es omitida por usuarios no privilegiados que acceden a la Interfaz de Usuario web. Este problema afecta a: Sistema Operativo Arista Metamako versión MOS-0.34.0 y versiones anteriores"
    }
  ],
  "lastModified": "2026-06-17T03:46:27.673",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:arista:metamako_operating_system:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "6C11D2B4-0389-4B23-B22A-1B0CB1B2299A",
              "versionEndIncluding": "0.34.0"
            }
          ],
          "operator": "OR"
        },
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:h:arista:7130:-:*:*:*:*:*:*:*",
              "vulnerable": false,
              "matchCriteriaId": "4D832798-DA45-4F9E-AA31-5D088253A28A"
            }
          ],
          "operator": "OR"
        }
      ],
      "operator": "AND"
    }
  ],
  "sourceIdentifier": "psirt@arista.com"
}