CVE-2026-83947

Status: Undergoing AnalysisHigh (7.7)—

Missing authorization in Azure Event Grid allows an authorized attacker to perform spoofing over a network.

CVSS

Version: 3.1
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:N
Base score: 7.7

Exploitation probability (EPSS)

Probability of exploitation in the next 30 days: 0.37%
Percentile among all scored CVEs: 29
Score date: 10/14/2026

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).

📰 Media coverage

Specialised security media that have cited this CVE:

NCSC-NL · NCSC-2026-0421 [1.00] [M/H] Kwetsbaarheden verholpen in Microsoft Azure (10/13/2026)

🎯 ATT&CK techniques

How this vulnerability is exploited and what the attacker gains, in MITRE ATT&CK terms.

ExploitationT1210 Exploitation of Remote Serviceslateral movement75 %
Primary impactT1078 Valid Accountsstealth · persistence · privilege escalation · initial access70 %
Secondary impactT1565.002 Transmitted Data Manipulationimpact65 %

AV:N/PR:L indica acceso remoto con privilegios: T1210. CWE-862 (autorización) y "spoofing" sugieren suplantación de identidad (T1078) y manipulación de datos (T1565.002). Confianza moderada por descripción breve.

Inferred by our analysis agent from the official description, CVSS vector and CWE, and checked by a supervisor. May contain errors.

🛡️ ATT&CK mitigations that cover these techniques

Privileged Account Management Application Developer Guidance Active Directory Configuration Vulnerability Scanning User Training User Account Management

Affected technologies (1)

⚠ AI-inferred from the description — NVD hasn't analyzed this CVE yet, these aren't verified CPEs.

Microsoft — Azure Event Grid^AI

CWEs

CWE-862

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-83947

Raw JSON (NVD)

Show

{
  "id": "CVE-2026-83947",
  "cveTags": [
    {
      "tags": [
        "exclusively-hosted-service"
      ],
      "sourceIdentifier": "secure@microsoft.com"
    }
  ],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-83947",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-10-09T13:11:07.720642Z"
        }
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "secure@microsoft.com",
        "cvssData": {
          "scope": "CHANGED",
          "version": "3.1",
          "baseScore": 7.7,
          "attackVector": "NETWORK",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:N",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "NONE",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 4,
        "exploitabilityScore": 3.1
      }
    ]
  },
  "affected": [
    {
      "source": "secure@microsoft.com",
      "affectedData": [
        {
          "vendor": "Microsoft",
          "product": "Azure Event Grid System",
          "versions": [
            {
              "status": "affected",
              "version": "-"
            }
          ]
        }
      ]
    }
  ],
  "published": "2026-10-08T23:17:04.423",
  "references": [
    {
      "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-83947",
      "source": "secure@microsoft.com"
    }
  ],
  "vulnStatus": "Undergoing Analysis",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "secure@microsoft.com",
      "description": [
        {
          "lang": "en",
          "value": "CWE-862"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "Missing authorization in Azure Event Grid allows an authorized attacker to perform spoofing over a network."
    }
  ],
  "lastModified": "2026-10-09T16:35:35.900",
  "sourceIdentifier": "secure@microsoft.com"
}