{
  "document": {
    "category": "csaf_security_advisory",
    "csaf_version": "2.0",
    "distribution": {
      "text": "Disclosure is not limited. (TLPv2: TLP:CLEAR)",
      "tlp": {
        "label": "WHITE"
      }
    },
    "lang": "en",
    "notes": [
      {
        "category": "summary",
        "text": "BACnet ATEC devices are affected by a denial of service vulnerability that could be triggered by an attacker residing in the same BACnet network by sending a specially crafted MSTP message. A power cycle is required to restore the device\u0027s normal operation.\n\nSiemens recommends countermeasures for products where fixes are not, or not yet available.",
        "title": "Summary"
      },
      {
        "category": "general",
        "text": "As a general security measure Siemens strongly recommends to protect network access to affected products with appropriate mechanisms. It is advised to follow recommended security practices in order to run the devices in a protected IT environment.",
        "title": "General Recommendations"
      },
      {
        "category": "general",
        "text": "For further inquiries on security vulnerabilities in Siemens products and solutions, please contact the Siemens ProductCERT: https://www.siemens.com/cert/advisories",
        "title": "Additional Resources"
      },
      {
        "category": "legal_disclaimer",
        "text": "The use of Siemens Security Advisories is subject to the terms and conditions listed on: https://www.siemens.com/productcert/terms-of-use.",
        "title": "Terms of Use"
      }
    ],
    "publisher": {
      "category": "vendor",
      "contact_details": "productcert@siemens.com",
      "name": "Siemens ProductCERT",
      "namespace": "https://www.siemens.com"
    },
    "references": [
      {
        "category": "self",
        "summary": "SSA-828116: Denial of Service Vulnerability in BACnet ATEC Devices - HTML Version",
        "url": "https://cert-portal.siemens.com/productcert/html/ssa-828116.html"
      },
      {
        "category": "self",
        "summary": "SSA-828116: Denial of Service Vulnerability in BACnet ATEC Devices - CSAF Version",
        "url": "https://cert-portal.siemens.com/productcert/csaf/ssa-828116.json"
      }
    ],
    "title": "SSA-828116: Denial of Service Vulnerability in BACnet ATEC Devices",
    "tracking": {
      "current_release_date": "2025-05-13T00:00:00Z",
      "generator": {
        "engine": {
          "name": "Siemens ProductCERT CSAF Generator",
          "version": "1"
        }
      },
      "id": "SSA-828116",
      "initial_release_date": "2025-05-13T00:00:00Z",
      "revision_history": [
        {
          "date": "2025-05-13T00:00:00Z",
          "legacy_version": "1.0",
          "number": "1",
          "summary": "Publication Date"
        }
      ],
      "status": "final",
      "version": "1"
    }
  },
  "product_tree": {
    "branches": [
      {
        "branches": [
          {
            "branches": [
              {
                "category": "product_version_range",
                "name": "vers:all/*",
                "product": {
                  "name": "BACnet ATEC 550-440",
                  "product_id": "1"
                }
              }
            ],
            "category": "product_name",
            "name": "BACnet ATEC 550-440"
          },
          {
            "branches": [
              {
                "category": "product_version_range",
                "name": "vers:all/*",
                "product": {
                  "name": "BACnet ATEC 550-441",
                  "product_id": "2"
                }
              }
            ],
            "category": "product_name",
            "name": "BACnet ATEC 550-441"
          },
          {
            "branches": [
              {
                "category": "product_version_range",
                "name": "vers:all/*",
                "product": {
                  "name": "BACnet ATEC 550-445",
                  "product_id": "3"
                }
              }
            ],
            "category": "product_name",
            "name": "BACnet ATEC 550-445"
          },
          {
            "branches": [
              {
                "category": "product_version_range",
                "name": "vers:all/*",
                "product": {
                  "name": "BACnet ATEC 550-446",
                  "product_id": "4"
                }
              }
            ],
            "category": "product_name",
            "name": "BACnet ATEC 550-446"
          }
        ],
        "category": "vendor",
        "name": "Siemens"
      }
    ]
  },
  "vulnerabilities": [
    {
      "cve": "CVE-2025-40556",
      "cwe": {
        "id": "CWE-20",
        "name": "Improper Input Validation"
      },
      "notes": [
        {
          "category": "summary",
          "text": "Affected devices improperly handle specific incoming BACnet MSTP messages. This could allow an attacker residing in the same BACnet network to send a specially crafted MSTP message that results in a denial of service condition of the targeted device. A power cycle is required to restore the device\u0027s normal operation.",
          "title": "Summary"
        }
      ],
      "product_status": {
        "known_affected": [
          "1",
          "2",
          "3",
          "4"
        ]
      },
      "remediations": [
        {
          "category": "no_fix_planned",
          "details": "Currently no fix is planned",
          "product_ids": [
            "1",
            "2",
            "3",
            "4"
          ]
        }
      ],
      "scores": [
        {
          "cvss_v3": {
            "baseScore": 6.5,
            "baseSeverity": "MEDIUM",
            "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
            "version": "3.1"
          },
          "products": [
            "1",
            "2",
            "3",
            "4"
          ]
        }
      ],
      "title": "CVE-2025-40556"
    }
  ]
}