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FKIE_CVE-2026-73443

Vulnerability from fkie_nvd - Published: 2026-09-16 19:17 - Updated: 2026-09-17 19:16
Severity
4.7 (Medium) - CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L
Summary
On affected platforms running Arista EOS with VRRPv2 IP-AH authentication configured, an unauthenticated attacker within the same layer 2 network segment on which VRRP is running can capture a legitimate authenticated VRRP advertisement and replay it indefinitely. Replayed advertisements can be used to advertise stale VRRP state, for example to prevent a backup router from taking over the virtual gateway after the original master has gone down, resulting in a denial of service for hosts using the virtual gateway address.
References
psirt@arista.comhttps://www.arista.com/en/support/advisories-notices/security-advisory/24713-security-advisory-0157
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "platforms": [
            "710 Series",
            "720D Series",
            "720XP/722XPM Series",
            "750X Series",
            "7010TX Series",
            "7020R/R4 Series",
            "7130 Series running EOS",
            "7170 Series",
            "7050X3/X4 Series",
            "7060X/X2/X4/X5/X6 Series",
            "7260X/X3 Series",
            "7280R/R2/R3/R4 Series",
            "7300X/X3 Series",
            "7320X Series",
            "7358X4 Series",
            "7368X4 Series",
            "7388X5 Series",
            "7500R/R2/R3 Series",
            "7800R3/R4 Series",
            "7700R4 Series",
            "AWE 5000 Series",
            "AWE 7200R Series",
            "CloudEOS",
            "cEOS-lab",
            "vEOS-lab",
            "CloudVision eXchange",
            "virtual or physical appliance"
          ],
          "product": "EOS",
          "vendor": "Arista Networks",
          "versions": [
            {
              "changes": [
                {
                  "at": "4.36.2F",
                  "status": "unaffected"
                }
              ],
              "lessThanOrEqual": "4.36.1F",
              "status": "affected",
              "version": "4.36.0",
              "versionType": "custom"
            },
            {
              "changes": [
                {
                  "at": "4.35.6M",
                  "status": "unaffected"
                }
              ],
              "lessThanOrEqual": "4.35.5M",
              "status": "affected",
              "version": "4.35.0",
              "versionType": "custom"
            },
            {
              "changes": [
                {
                  "at": "4.34.8M",
                  "status": "unaffected"
                }
              ],
              "lessThanOrEqual": "4.34.7M",
              "status": "affected",
              "version": "4.34.0",
              "versionType": "custom"
            },
            {
              "changes": [
                {
                  "at": "4.33.10M",
                  "status": "unaffected"
                }
              ],
              "lessThanOrEqual": "4.33.9M",
              "status": "affected",
              "version": "4.33.0",
              "versionType": "custom"
            }
          ]
        }
      ],
      "source": "psirt@arista.com"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "On affected platforms running Arista EOS with VRRPv2 IP-AH authentication configured, an unauthenticated attacker within the same layer 2 network segment on which VRRP is running can capture a legitimate authenticated VRRP advertisement and replay it indefinitely. Replayed advertisements can be used to advertise stale VRRP state, for example to prevent a backup router from taking over the virtual gateway after the original master has gone down, resulting in a denial of service for hosts using the virtual gateway address."
    }
  ],
  "id": "CVE-2026-73443",
  "lastModified": "2026-09-17T19:16:57.003",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "ADJACENT_NETWORK",
          "availabilityImpact": "LOW",
          "baseScore": 4.7,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "CHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L",
          "version": "3.1"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 1.4,
        "source": "psirt@arista.com",
        "type": "Secondary"
      }
    ],
    "cvssMetricV40": [
      {
        "cvssData": {
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "attackComplexity": "LOW",
          "attackRequirements": "NONE",
          "attackVector": "ADJACENT",
          "availabilityRequirement": "NOT_DEFINED",
          "baseScore": 5.3,
          "baseSeverity": "MEDIUM",
          "confidentialityRequirement": "NOT_DEFINED",
          "exploitMaturity": "NOT_DEFINED",
          "integrityRequirement": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "privilegesRequired": "NONE",
          "providerUrgency": "NOT_DEFINED",
          "subAvailabilityImpact": "NONE",
          "subConfidentialityImpact": "NONE",
          "subIntegrityImpact": "NONE",
          "userInteraction": "NONE",
          "valueDensity": "NOT_DEFINED",
          "vectorString": "CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
          "version": "4.0",
          "vulnAvailabilityImpact": "LOW",
          "vulnConfidentialityImpact": "NONE",
          "vulnIntegrityImpact": "NONE",
          "vulnerabilityResponseEffort": "NOT_DEFINED"
        },
        "source": "psirt@arista.com",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-73443",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-09-17T18:33:08.446292Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-09-16T19:17:31.330",
  "references": [
    {
      "source": "psirt@arista.com",
      "url": "https://www.arista.com/en/support/advisories-notices/security-advisory/24713-security-advisory-0157"
    }
  ],
  "sourceIdentifier": "psirt@arista.com",
  "vulnStatus": "Awaiting Analysis",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-294"
        }
      ],
      "source": "psirt@arista.com",
      "type": "Secondary"
    }
  ]
}



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