CVE-2026-76404 (GCVE-0-2026-76404)

Vulnerability from cvelistv5 – Published: 2026-08-19 21:35 – Updated: 2026-08-20 15:26
VLAI
Title
Remote Code Execution (RCE) through Deserialization of Untrusted Data in Splunk MCP Server app
Summary
In Splunk MCP Server app versions below 1.2.1, a user who holds the "admin" Splunk role could execute arbitrary commands on the underlying operating system. The vulnerability is possible because of missing input validation in the app's credential management component, which deserializes stored data without checking whether the content is of the expected type.
Severity
9.1 (Critical)
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
SSVC
Exploitation: none Automatable: no Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-08-20 15:09 UTC
CWE
  • CWE-502 - The application deserializes untrusted data without sufficiently verifying that the resulting data will be valid.
Assigner
cisco CNA under the mitre root
CNA scorecard C 66/100 over 443 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Splunk Splunk MCP Server app Affected: 1.2 , < 1.2.1 (custom)
guessed Create a notification for this product.
Date Public
2026-08-19 00:00
Credits
Kuniyoshi Noguchi (KuniNogu)
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-76404",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-08-20T15:09:45.301346Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-08-20T15:26:31.137Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "Splunk MCP Server app",
          "vendor": "Splunk",
          "versions": [
            {
              "lessThan": "1.2.1",
              "status": "affected",
              "version": "1.2",
              "versionType": "custom"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "reporter",
          "value": "Kuniyoshi Noguchi (KuniNogu)"
        }
      ],
      "datePublic": "2026-08-19T00:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/markdown",
              "value": "In Splunk MCP Server app versions below 1.2.1, a user who holds the \"admin\" Splunk role could execute arbitrary commands on the underlying operating system. The vulnerability is possible because of missing input validation in the app\u0027s credential management component, which deserializes stored data without checking whether the content is of the expected type."
            }
          ],
          "value": "In Splunk MCP Server app versions below 1.2.1, a user who holds the \"admin\" Splunk role could execute arbitrary commands on the underlying operating system. The vulnerability is possible because of missing input validation in the app\u0027s credential management component, which deserializes stored data without checking whether the content is of the expected type."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 9.1,
            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H",
            "version": "3.1"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-502",
              "description": "The application deserializes untrusted data without sufficiently verifying that the resulting data will be valid.",
              "lang": "en",
              "type": "cwe"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-19T21:35:17.448Z",
        "orgId": "d1c1063e-7a18-46af-9102-31f8928bc633",
        "shortName": "cisco"
      },
      "references": [
        {
          "url": "https://advisory.splunk.com/advisories/SVD-2026-0808"
        }
      ],
      "solutions": [
        {
          "lang": "en",
          "value": "Upgrade each affected Splunk app or add-on to the applicable fixed version listed in Product Status."
        }
      ],
      "source": {
        "advisory": "SVD-2026-0808"
      },
      "title": "Remote Code Execution (RCE) through Deserialization of Untrusted Data in Splunk MCP Server app",
      "workarounds": [
        {
          "lang": "en",
          "value": "Turn off or remove the Splunk MCP Server app. For more information see [Manage app and add-on objects](https://help.splunk.com/en/splunk-enterprise/administer/admin-manual/10.2/meet-splunk-apps/manage-app-and-add-on-objects) in the Splunk documentation."
        }
      ]
    }
  },
  "cveMetadata": {
    "assignerOrgId": "d1c1063e-7a18-46af-9102-31f8928bc633",
    "assignerShortName": "cisco",
    "cveId": "CVE-2026-76404",
    "datePublished": "2026-08-19T21:35:17.448Z",
    "dateReserved": "2026-08-19T12:02:03.632Z",
    "dateUpdated": "2026-08-20T15:26:31.137Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-76404",
      "date": "2026-11-01",
      "epss": "0.00749",
      "percentile": "0.5494"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "product": "Splunk MCP Server app",
                "vendor": "Splunk",
                "versions": [
                  {
                    "lessThan": "1.2.1",
                    "status": "affected",
                    "version": "1.2",
                    "versionType": "custom"
                  }
                ]
              }
            ],
            "source": "psirt@cisco.com"
          }
        ],
        "configurations": [
          {
            "nodes": [
              {
                "cpeMatch": [
                  {
                    "criteria": "cpe:2.3:a:splunk:model_context_protocol_server:*:*:*:*:*:*:*:*",
                    "matchCriteriaId": "D34DCE3E-FC83-4D4F-91BF-A2AD23B38838",
                    "versionEndExcluding": "1.2.1",
                    "vulnerable": true
                  }
                ],
                "negate": false,
                "operator": "OR"
              }
            ]
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In Splunk MCP Server app versions below 1.2.1, a user who holds the \"admin\" Splunk role could execute arbitrary commands on the underlying operating system. The vulnerability is possible because of missing input validation in the app\u0027s credential management component, which deserializes stored data without checking whether the content is of the expected type."
          },
          {
            "lang": "es",
            "value": "En las versiones de la aplicaci\u00f3n Splunk MCP Server anteriores a la 1.2.1, un usuario con el rol de Splunk \u2019admin\u2019 podr\u00eda ejecutar comandos arbitrarios en el sistema operativo subyacente. La vulnerabilidad es posible debido a la falta de validaci\u00f3n de entrada en el componente de gesti\u00f3n de credenciales de la aplicaci\u00f3n, que deserializa datos almacenados sin comprobar si el contenido es del tipo esperado."
          }
        ],
        "id": "CVE-2026-76404",
        "lastModified": "2026-10-24T13:10:00.147",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "NETWORK",
                "availabilityImpact": "HIGH",
                "baseScore": 9.1,
                "baseSeverity": "CRITICAL",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "HIGH",
                "scope": "CHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H",
                "version": "3.1"
              },
              "exploitabilityScore": 2.3,
              "impactScore": 6.0,
              "source": "psirt@cisco.com",
              "type": "Secondary"
            }
          ],
          "ssvcV203": [
            {
              "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "ssvcData": {
                "id": "CVE-2026-76404",
                "options": [
                  {
                    "exploitation": "none"
                  },
                  {
                    "automatable": "no"
                  },
                  {
                    "technicalImpact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-08-20T15:09:45.301346Z",
                "version": "2.0.3"
              }
            }
          ]
        },
        "published": "2026-08-19T22:17:27.170",
        "references": [
          {
            "source": "psirt@cisco.com",
            "tags": [
              "Vendor Advisory"
            ],
            "url": "https://advisory.splunk.com/advisories/SVD-2026-0808"
          }
        ],
        "sourceIdentifier": "psirt@cisco.com",
        "vulnStatus": "Analyzed",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-502"
              }
            ],
            "source": "psirt@cisco.com",
            "type": "Secondary"
          }
        ]
      }
    },
    "vulnrichment": {
      "containers": {
        "adp": [
          {
            "metrics": [
              {
                "other": {
                  "content": {
                    "id": "CVE-2026-76404",
                    "options": [
                      {
                        "Exploitation": "none"
                      },
                      {
                        "Automatable": "no"
                      },
                      {
                        "Technical Impact": "total"
                      }
                    ],
                    "role": "CISA Coordinator",
                    "timestamp": "2026-08-20T15:09:45.301346Z",
                    "version": "2.0.3"
                  },
                  "type": "ssvc"
                }
              }
            ],
            "providerMetadata": {
              "dateUpdated": "2026-08-20T15:23:55.839Z",
              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP"
            },
            "title": "CISA ADP Vulnrichment"
          }
        ],
        "cna": {
          "affected": [
            {
              "product": "Splunk MCP Server app",
              "vendor": "Splunk",
              "versions": [
                {
                  "lessThan": "1.2.1",
                  "status": "affected",
                  "version": "1.2",
                  "versionType": "custom"
                }
              ]
            }
          ],
          "credits": [
            {
              "lang": "en",
              "type": "reporter",
              "value": "Kuniyoshi Noguchi (KuniNogu)"
            }
          ],
          "datePublic": "2026-08-19T00:00:00.000Z",
          "descriptions": [
            {
              "lang": "en",
              "supportingMedia": [
                {
                  "base64": false,
                  "type": "text/markdown",
                  "value": "In Splunk MCP Server app versions below 1.2.1, a user who holds the \"admin\" Splunk role could execute arbitrary commands on the underlying operating system. The vulnerability is possible because of missing input validation in the app\u0027s credential management component, which deserializes stored data without checking whether the content is of the expected type."
                }
              ],
              "value": "In Splunk MCP Server app versions below 1.2.1, a user who holds the \"admin\" Splunk role could execute arbitrary commands on the underlying operating system. The vulnerability is possible because of missing input validation in the app\u0027s credential management component, which deserializes stored data without checking whether the content is of the expected type."
            }
          ],
          "metrics": [
            {
              "cvssV3_1": {
                "baseScore": 9.1,
                "baseSeverity": "CRITICAL",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H",
                "version": "3.1"
              },
              "format": "CVSS",
              "scenarios": [
                {
                  "lang": "en",
                  "value": "GENERAL"
                }
              ]
            }
          ],
          "problemTypes": [
            {
              "descriptions": [
                {
                  "cweId": "CWE-502",
                  "description": "The application deserializes untrusted data without sufficiently verifying that the resulting data will be valid.",
                  "lang": "en",
                  "type": "cwe"
                }
              ]
            }
          ],
          "providerMetadata": {
            "dateUpdated": "2026-08-19T21:35:17.448Z",
            "orgId": "d1c1063e-7a18-46af-9102-31f8928bc633",
            "shortName": "cisco"
          },
          "references": [
            {
              "url": "https://advisory.splunk.com/advisories/SVD-2026-0808"
            }
          ],
          "solutions": [
            {
              "lang": "en",
              "value": "Upgrade each affected Splunk app or add-on to the applicable fixed version listed in Product Status."
            }
          ],
          "source": {
            "advisory": "SVD-2026-0808"
          },
          "title": "Remote Code Execution (RCE) through Deserialization of Untrusted Data in Splunk MCP Server app",
          "workarounds": [
            {
              "lang": "en",
              "value": "Turn off or remove the Splunk MCP Server app. For more information see [Manage app and add-on objects](https://help.splunk.com/en/splunk-enterprise/administer/admin-manual/10.2/meet-splunk-apps/manage-app-and-add-on-objects) in the Splunk documentation."
            }
          ]
        }
      },
      "cveMetadata": {
        "assignerOrgId": "d1c1063e-7a18-46af-9102-31f8928bc633",
        "assignerShortName": "cisco",
        "cveId": "CVE-2026-76404",
        "datePublished": "2026-08-19T21:35:17.448Z",
        "dateReserved": "2026-08-19T12:02:03.632Z",
        "dateUpdated": "2026-08-20T15:26:31.137Z",
        "state": "PUBLISHED"
      },
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Drag nodes to arrange them. Double-click a related vulnerability to open it, or a source to visit its link. The Physics button on the left tunes the layout and the simulation; the legend at the bottom left hides or shows nodes by kind and by sighting type.

Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

JSON

Loading timeline…




    Related by attack behaviour

    Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.