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CVE-2026-66305 (GCVE-0-2026-66305)

Vulnerability from cvelistv5 – Published: 2026-09-08 18:32 – Updated: 2026-09-08 23:35
VLAI
Title
Skype for Business Spoofing Vulnerability
Summary
Use of client-side authentication in Skype for Business allows an authorized attacker to perform spoofing over a network.
Severity
7.1 (High)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N/E:U/RL:O/RC:C
CWE
  • CWE-603 - Use of Client-Side Authentication
Assigner
References
Impacted products
Vendor Product Version CPE status
Microsoft Skype for Business Server 2015 CU13 Affected: 9319.0 , < 6.0.9319.885 (custom)
guessed Create a notification for this product.
Microsoft Skype for Business Server 2019 CU8 Affected: 2046.0 , < 7.0.2046.569 (custom)
guessed Create a notification for this product.
Microsoft Skype for Business Server Subscription Edition CU1 Affected: 2046.0 , < 7.0.2046.879 (custom)
guessed Create a notification for this product.
Date Public
2026-09-08 14:00
Show details on NVD website
To clipboard 

{
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        {
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            "x64-based Systems"
          ],
          "product": "Skype for Business Server 2015 CU13",
          "vendor": "Microsoft",
          "versions": [
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              "version": "9319.0",
              "versionType": "custom"
            }
          ]
        },
        {
          "platforms": [
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          ],
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          "vendor": "Microsoft",
          "versions": [
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            }
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          ],
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          "vendor": "Microsoft",
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              "status": "affected",
              "version": "2046.0",
              "versionType": "custom"
            }
          ]
        }
      ],
      "cpeApplicability": [
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              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:a:microsoft:skype_for_business_server_2015:*:cu13:*:*:*:*:*:*",
                  "versionEndExcluding": "6.0.9319.885",
                  "versionStartIncluding": "9319.0",
                  "vulnerable": true
                },
                {
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                  "versionEndExcluding": "7.0.2046.569",
                  "versionStartIncluding": "2046.0",
                  "vulnerable": true
                },
                {
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                  "versionEndExcluding": "7.0.2046.879",
                  "versionStartIncluding": "2046.0",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "datePublic": "2026-09-08T14:00:00.000Z",
      "descriptions": [
        {
          "lang": "en-US",
          "value": "Use of client-side authentication in Skype for Business allows an authorized attacker to perform spoofing over a network."
        }
      ],
      "metrics": [
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            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N/E:U/RL:O/RC:C",
            "version": "3.1"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en-US",
              "value": "GENERAL"
            }
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        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-603",
              "description": "CWE-603: Use of Client-Side Authentication",
              "lang": "en-US",
              "type": "CWE"
            }
          ]
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      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-08T23:35:21.399Z",
        "orgId": "f38d906d-7342-40ea-92c1-6c4a2c6478c8",
        "shortName": "microsoft"
      },
      "references": [
        {
          "name": "Skype for Business Spoofing Vulnerability",
          "tags": [
            "vendor-advisory",
            "patch"
          ],
          "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-66305"
        }
      ],
      "title": "Skype for Business Spoofing Vulnerability"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "f38d906d-7342-40ea-92c1-6c4a2c6478c8",
    "assignerShortName": "microsoft",
    "cveId": "CVE-2026-66305",
    "datePublished": "2026-09-08T18:32:29.324Z",
    "dateReserved": "2026-07-24T18:06:51.294Z",
    "dateUpdated": "2026-09-08T23:35:21.399Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "microsoft_vex": {
      "current_release_date": "2026-09-08T07:00:00.000Z",
      "cve": "CVE-2026-66305",
      "id": "msrc_CVE-2026-66305",
      "initial_release_date": "2026-09-08T07:00:00.000Z",
      "product_status:fixed": "3",
      "product_status:known_affected": "3",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "Skype for Business Spoofing Vulnerability",
      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-66305.json",
      "version": "1"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-66305\",\"sourceIdentifier\":\"secure@microsoft.com\",\"published\":\"2026-09-08T19:18:08.073\",\"lastModified\":\"2026-09-08T19:22:18.470\",\"vulnStatus\":\"Undergoing Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"Use of client-side authentication in Skype for Business allows an authorized attacker to perform spoofing over a network.\"}],\"affected\":[{\"source\":\"secure@microsoft.com\",\"affectedData\":[{\"vendor\":\"Microsoft\",\"product\":\"Skype for Business Server 2015 CU13\",\"platforms\":[\"x64-based Systems\"],\"versions\":[{\"version\":\"9319.0\",\"lessThan\":\"6.0.9319.885\",\"versionType\":\"custom\",\"status\":\"affected\"}]},{\"vendor\":\"Microsoft\",\"product\":\"Skype for Business Server 2019 CU8\",\"platforms\":[\"x64-based Systems\"],\"versions\":[{\"version\":\"2046.0\",\"lessThan\":\"7.0.2046.569\",\"versionType\":\"custom\",\"status\":\"affected\"}]},{\"vendor\":\"Microsoft\",\"product\":\"Skype for Business Server Subscription Edition CU1\",\"platforms\":[\"x64-based Systems\"],\"versions\":[{\"version\":\"2046.0\",\"lessThan\":\"7.0.2046.879\",\"versionType\":\"custom\",\"status\":\"affected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"secure@microsoft.com\",\"type\":\"Primary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N\",\"baseScore\":7.1,\"baseSeverity\":\"HIGH\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"LOW\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"NONE\"},\"exploitabilityScore\":2.8,\"impactScore\":4.2}]},\"weaknesses\":[{\"source\":\"secure@microsoft.com\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-603\"}]}],\"references\":[{\"url\":\"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-66305\",\"source\":\"secure@microsoft.com\"}]}}"
  }
}



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