CVE-2026-76286

Status: Awaiting AnalysisMedium (5.3)—

In Splunk MCP Server versions below 1.2.1, Splunk MCP Server could send the Splunk platform authentication token of a user who runs a custom Application Programming Interface (API) tool to the URL configured for that tool. If another user controls that URL, they could capture the token and use it to access data and perform actions as the user who ran the tool. Successful exploitation requires a user who holds a role that contains the mcp_tool_execute capability to run a custom API tool configured by another user.

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For more information see Configure the Splunk MCP Server (https://help.splunk.com/en/splunk-enterprise/mcp-server-for-splunk-platform/1.2/configure-the-splunk-mcp-server) and Managing custom tools in Splunk MCP Server (https://help.splunk.com/en/splunk-enterprise/mcp-server-for-splunk-platform/1.2/managing-custom-tools-in-splunk-mcp-server) in the Splunk documentation.

CVSS

Version: 3.1
Vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:H/I:L/A:L
Base score: 5.3

Exploitation probability (EPSS)

Probability of exploitation in the next 30 days: 0.17%
Percentile among all scored CVEs: 6
Score date: 10/13/2026

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).

🎯 ATT&CK techniques

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

ExploitationT1203 Exploitation for Client Executionexecution75 %
Primary impactT1212 Exploitation for Credential Accesscredential access85 %
Secondary impactT1078 Valid Accountsstealth · persistence · privilege escalation · initial access80 %

UI:R y PR:H requieren interacción del usuario (ejecutar herramienta) con privilegios. El atacante captura token de autenticación (T1212) para acceder como otro usuario (T1078). CWE-918 (SSRF) respalda envío a URL controlada.

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

Application Developer Guidance Application Isolation and Sandboxing Exploit Protection Update Software Active Directory Configuration User Training

Affected technologies (1)

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

Splunk — MCP Server^AI

CWEs

CWE-918

References

https://advisory.splunk.com/advisories/SVD-2026-1004

Raw JSON (NVD)

Show

{
  "id": "CVE-2026-76286",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-76286",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-10-08T18:00:12.979178Z"
        }
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "psirt@cisco.com",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 5.3,
          "attackVector": "NETWORK",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:H/I:L/A:L",
          "integrityImpact": "LOW",
          "userInteraction": "REQUIRED",
          "attackComplexity": "HIGH",
          "availabilityImpact": "LOW",
          "privilegesRequired": "HIGH",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 4.7,
        "exploitabilityScore": 0.5
      }
    ]
  },
  "affected": [
    {
      "source": "psirt@cisco.com",
      "affectedData": [
        {
          "vendor": "Splunk",
          "modules": [
            "REST API"
          ],
          "product": "Splunk MCP Server",
          "versions": [
            {
              "status": "affected",
              "version": "1.2",
              "lessThan": "1.2.1",
              "versionType": "custom"
            }
          ]
        }
      ]
    }
  ],
  "published": "2026-10-07T21:17:20.387",
  "references": [
    {
      "url": "https://advisory.splunk.com/advisories/SVD-2026-1004",
      "source": "psirt@cisco.com"
    }
  ],
  "vulnStatus": "Awaiting Analysis",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "psirt@cisco.com",
      "description": [
        {
          "lang": "en",
          "value": "CWE-918"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "In Splunk MCP Server versions below 1.2.1, Splunk MCP Server could send the Splunk platform authentication token of a user who runs a custom Application Programming Interface (API) tool to the URL configured for that tool. If another user controls that URL, they could capture the token and use it to access data and perform actions as the user who ran the tool. Successful exploitation requires a user who holds a role that contains the mcp_tool_execute capability to run a custom API tool configured by another user. For more information see Configure the Splunk MCP Server (https://help.splunk.com/en/splunk-enterprise/mcp-server-for-splunk-platform/1.2/configure-the-splunk-mcp-server) and Managing custom tools in Splunk MCP Server (https://help.splunk.com/en/splunk-enterprise/mcp-server-for-splunk-platform/1.2/managing-custom-tools-in-splunk-mcp-server) in the Splunk documentation."
    }
  ],
  "lastModified": "2026-10-08T20:08:45.857",
  "sourceIdentifier": "psirt@cisco.com"
}