{
  "document": {
    "acknowledgments": [
      {
        "names": [
          "Anonymous"
        ]
      }
    ],
    "aggregate_severity": {
      "namespace": "https://www.microsoft.com/en-us/msrc/security-update-severity-rating-system",
      "text": "Important"
    },
    "category": "csaf_security_advisory",
    "csaf_version": "2.0",
    "distribution": {
      "text": "Public",
      "tlp": {
        "label": "WHITE",
        "url": "https://www.first.org/tlp/"
      }
    },
    "lang": "en-US",
    "notes": [
      {
        "category": "general",
        "text": "To determine the support lifecycle for your software, see the Microsoft Support Lifecycle: https://support.microsoft.com/lifecycle",
        "title": "Additional Resources"
      },
      {
        "category": "legal_disclaimer",
        "text": "The information provided in the Microsoft Knowledge Base is provided \\\"as is\\\" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.",
        "title": "Disclaimer"
      },
      {
        "category": "general",
        "text": "Required. The vulnerability documented by this CVE requires customer action to resolve.",
        "title": "Customer Action"
      }
    ],
    "publisher": {
      "category": "vendor",
      "contact_details": "secure@microsoft.com",
      "name": "Microsoft Security Response Center",
      "namespace": "https://msrc.microsoft.com"
    },
    "references": [
      {
        "category": "self",
        "summary": "CVE-2026-40372 ASP.NET Core Elevation of Privilege Vulnerability - HTML",
        "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-40372"
      },
      {
        "category": "self",
        "summary": "CVE-2026-40372 ASP.NET Core Elevation of Privilege Vulnerability - CSAF",
        "url": "https://msrc.microsoft.com/csaf/advisories/2026/msrc_cve-2026-40372.json"
      },
      {
        "category": "external",
        "summary": "Microsoft Exploitability Index",
        "url": "https://www.microsoft.com/en-us/msrc/exploitability-index?rtc=1"
      },
      {
        "category": "external",
        "summary": "Microsoft Support Lifecycle",
        "url": "https://support.microsoft.com/lifecycle"
      },
      {
        "category": "external",
        "summary": "Common Vulnerability Scoring System",
        "url": "https://www.first.org/cvss"
      }
    ],
    "title": "ASP.NET Core Elevation of Privilege Vulnerability",
    "tracking": {
      "current_release_date": "2026-04-21T07:00:00.000Z",
      "generator": {
        "date": "2026-04-21T19:19:05.268Z",
        "engine": {
          "name": "MSRC Generator",
          "version": "1.0"
        }
      },
      "id": "msrc_CVE-2026-40372",
      "initial_release_date": "2026-04-14T07:00:00.000Z",
      "revision_history": [
        {
          "date": "2026-04-21T07:00:00.000Z",
          "legacy_version": "1",
          "number": "1",
          "summary": "Information published."
        }
      ],
      "status": "final",
      "version": "1"
    }
  },
  "product_tree": {
    "branches": [
      {
        "branches": [
          {
            "category": "product_version_range",
            "name": "\u003c10.0.7",
            "product": {
              "name": "ASP.NET Core 10.0 \u003c10.0.7",
              "product_id": "1"
            }
          },
          {
            "category": "product_version",
            "name": "10.0.7",
            "product": {
              "name": "ASP.NET Core 10.0 10.0.7",
              "product_id": "20932"
            }
          }
        ],
        "category": "product_name",
        "name": "ASP.NET Core 10.0"
      }
    ]
  },
  "vulnerabilities": [
    {
      "cve": "CVE-2026-40372",
      "cwe": {
        "id": "CWE-347",
        "name": "Improper Verification of Cryptographic Signature"
      },
      "notes": [
        {
          "category": "general",
          "text": "Microsoft",
          "title": "Assigning CNA"
        },
        {
          "category": "faq",
          "text": "An attacker who successfully exploited this vulnerability could gain SYSTEM privileges.",
          "title": "What privileges could be gained by an attacker who successfully exploited this vulnerability?"
        },
        {
          "category": "faq",
          "text": "You are affected if all three of the following are true:\nYour application uses Microsoft.AspNetCore.DataProtection 10.0.6 from NuGet (directly, or through a package that depends on it such as Microsoft.AspNetCore.DataProtection.StackExchangeRedis).\nThe NuGet copy of the library was actually loaded at runtime \u2014 not the shared framework copy. This typically means you deploy self-contained, or your installed shared framework is older than the NuGet package version.\nYour application runs on Linux, macOS, or another non-Windows OS.\nHow do I determine if the vulnerable binary was loaded?\nCheck application logs. The clearest symptom is users being logged out and repeated \u0026quot;The payload was invalid\u0026quot; errors in your logs after upgrading to 10.0.6.\nCheck your project file. Look for a PackageReference to Microsoft.AspNetCore.DataProtection version 10.0.6 in your .csproj file (or in a package that depends on it). You can also run dotnet list package to see resolved package versions.\nInspect the binary on disk. See [https://file+.vscode-resource.vscode-cdn.net/c%3A/Users/shalter/Downloads/advisory-upd-1.md#technical-details]Technical details for how to distinguish the affected NuGet binary from the correct shared framework binary by file size.\nShared framework deployments are not affected. If your application runs framework-dependent and the installed ASP.NET Core shared framework version is \u2265 your Microsoft.AspNetCore.DataProtection PackageReference version, the correct shared framework binary is loaded and the NuGet binary is never used.\nWindows deployments are not affected. On Windows, DataProtection uses CNG-based encryptors by default, which do not contain this bug. 8.0.x and 9.0.x packages are not affected. The defective code path was introduced during 10.0 development and was never backported.\nWindows with managed algorithms: If you run on Windows but explicitly opted into managed algorithms via UseCustomCryptographicAlgorithms, you are also affected.\nOlder target frameworks: A smaller population running net462 / netstandard2.0 with Microsoft.AspNetCore.DataProtection 10.0.0\u201310.0.6 is affected on all operating systems. See [https://file+.vscode-resource.vscode-cdn.net/c%3A/Users/shalter/Downloads/advisory-upd-1.md#technical-details]Technical details for specifics.\nhttps://github.com/dotnet/announcements/issues/395",
          "title": "How do I know if I\u0027m affected?"
        },
        {
          "category": "faq",
          "text": "Exploiting this vulnerability could allow an attacker to disclose files and modify data, but the attacker cannot impact the availability of the system.",
          "title": "According to the CVSS metrics, successful exploitation of this vulnerability could lead to major loss of confidentiality (C:H), and integrity (I:H), but could lead to no loss of availability (A:N). What does that mean for this vulnerability?"
        }
      ],
      "product_status": {
        "fixed": [
          "20932"
        ],
        "known_affected": [
          "1"
        ]
      },
      "references": [
        {
          "category": "self",
          "summary": "CVE-2026-40372 ASP.NET Core Elevation of Privilege Vulnerability - HTML",
          "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-40372"
        },
        {
          "category": "self",
          "summary": "CVE-2026-40372 ASP.NET Core Elevation of Privilege Vulnerability - CSAF",
          "url": "https://msrc.microsoft.com/csaf/advisories/2026/msrc_cve-2026-40372.json"
        }
      ],
      "remediations": [
        {
          "category": "vendor_fix",
          "date": "2026-04-21T07:00:00.000Z",
          "details": "10.0.7:Security Update:https://support.microsoft.com/help/5091596",
          "product_ids": [
            "1"
          ],
          "url": "https://support.microsoft.com/help/5091596"
        }
      ],
      "scores": [
        {
          "cvss_v3": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 9.1,
            "baseSeverity": "CRITICAL",
            "confidentialityImpact": "HIGH",
            "environmentalsScore": 0.0,
            "exploitCodeMaturity": "UNPROVEN",
            "integrityImpact": "HIGH",
            "privilegesRequired": "NONE",
            "remediationLevel": "OFFICIAL_FIX",
            "reportConfidence": "CONFIRMED",
            "scope": "UNCHANGED",
            "temporalScore": 7.9,
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N/E:U/RL:O/RC:C",
            "version": "3.1"
          },
          "products": [
            "1"
          ]
        }
      ],
      "threats": [
        {
          "category": "impact",
          "details": "Elevation of Privilege"
        },
        {
          "category": "exploit_status",
          "details": "Publicly Disclosed:No;Exploited:No;Latest Software Release:Exploitation Less Likely"
        }
      ],
      "title": "ASP.NET Core Elevation of Privilege Vulnerability"
    }
  ]
}