{
  "cveId": "CVE-2026-21265",
  "url": "https://patchblox.com/security/cve/CVE-2026-21265",
  "summary": "CVE-2026-21265 is fixed in 29 products on 1 platform, first by KB5073722, released January 13, 2026. It is not reported as exploited. Patch Radar priority: Routine.",
  "title": "Secure Boot Certificate Expiration Security Feature Bypass Vulnerability",
  "description": "\u003Cp\u003EWindows Secure Boot stores Microsoft certificates in the UEFI KEK and DB. These original certificates are approaching expiration, and devices containing affected certificate versions must update them to maintain Secure Boot functionality and avoid compromising security by losing security fixes related to Windows boot manager or Secure Boot.\u003C/p\u003E\n\u003Cp\u003EThe operating system\u2019s certificate update protection mechanism relies on firmware components that might contain defects, which can cause certificate trust updates to fail or behave unpredictably. This leads to potential disruption of the Secure Boot trust chain and requires careful validation and deployment to restore intended security guarantees.\u003C/p\u003E\n\u003Ctable\u003E\n\u003Cthead\u003E\n\u003Ctr\u003E\n\u003Cth\u003ECertificate Authority (CA)\u003C/th\u003E\n\u003Cth\u003ELocation\u003C/th\u003E\n\u003Cth\u003EPurpose\u003C/th\u003E\n\u003Cth\u003EExpiration Date\u003C/th\u003E\n\u003C/tr\u003E\n\u003C/thead\u003E\n\u003Ctbody\u003E\n\u003Ctr\u003E\n\u003Ctd\u003EMicrosoft Corporation KEK CA 2011\u003C/td\u003E\n\u003Ctd\u003EKEK\u003C/td\u003E\n\u003Ctd\u003ESigns updates to the DB and DBX\u003C/td\u003E\n\u003Ctd\u003E06/24/2026\u003C/td\u003E\n\u003C/tr\u003E\n\u003Ctr\u003E\n\u003Ctd\u003EMicrosoft Corporation UEFI CA 2011\u003C/td\u003E\n\u003Ctd\u003EDB\u003C/td\u003E\n\u003Ctd\u003ESigns 3rd party boot loaders, Option ROMs, etc.\u003C/td\u003E\n\u003Ctd\u003E06/27/2026\u003C/td\u003E\n\u003C/tr\u003E\n\u003Ctr\u003E\n\u003Ctd\u003EMicrosoft Windows Production PCA 2011\u003C/td\u003E\n\u003Ctd\u003EDB\u003C/td\u003E\n\u003Ctd\u003ESigns the Windows Boot Manager\u003C/td\u003E\n\u003Ctd\u003E10/19/2026\u003C/td\u003E\n\u003C/tr\u003E\n\u003C/tbody\u003E\n\u003C/table\u003E\n\u003Cp\u003EFor more information see this CVE and \u003Ca href=\u0022https://aka.ms/GetSecureBoot\u0022\u003EWindows Secure Boot certificate expiration and CA updates\u003C/a\u003E.\u003C/p\u003E",
  "published": "2026-01-13T08:00:00Z",
  "severity": "Important",
  "cvss": 6.4,
  "epss": 0.01096,
  "epssPercentile": 0.65811,
  "priority": "Routine",
  "priorityTier": 4,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": true,
  "exploitabilityAssessment": "Exploitation Less Likely",
  "vendorAdvisory": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21265",
  "fixes": [
    {
      "platform": "microsoft",
      "product": "Windows 10 Version 1607 for 32-bit Systems",
      "fixedVersion": "14393.8783",
      "fix": "KB5073722",
      "url": "https://patchblox.com/security/fix/microsoft/kb5073722",
      "released": "2026-01-13T00:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows 10 Version 1607 for x64-based Systems",
      "fixedVersion": "14393.8783",
      "fix": "KB5073722",
      "url": "https://patchblox.com/security/fix/microsoft/kb5073722",
      "released": "2026-01-13T00:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows 10 Version 1809 for 32-bit Systems",
      "fixedVersion": "17763.8276",
      "fix": "KB5073723",
      "url": "https://patchblox.com/security/fix/microsoft/kb5073723",
      "released": "2026-01-13T00:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows 10 Version 1809 for x64-based Systems",
      "fixedVersion": "17763.8276",
      "fix": "KB5073723",
      "url": "https://patchblox.com/security/fix/microsoft/kb5073723",
      "released": "2026-01-13T00:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows 10 Version 21H2 for 32-bit Systems",
      "fixedVersion": "",
      "fix": "KB5073724",
      "url": "https://patchblox.com/security/fix/microsoft/kb5073724",
      "released": "2026-01-13T00:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows 10 Version 21H2 for ARM64-based Systems",
      "fixedVersion": "",
      "fix": "KB5073724",
      "url": "https://patchblox.com/security/fix/microsoft/kb5073724",
      "released": "2026-01-13T00:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows 10 Version 21H2 for x64-based Systems",
      "fixedVersion": "",
      "fix": "KB5073724",
      "url": "https://patchblox.com/security/fix/microsoft/kb5073724",
      "released": "2026-01-13T00:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows 10 Version 22H2 for 32-bit Systems",
      "fixedVersion": "",
      "fix": "KB5073724",
      "url": "https://patchblox.com/security/fix/microsoft/kb5073724",
      "released": "2026-01-13T00:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows 10 Version 22H2 for ARM64-based Systems",
      "fixedVersion": "",
      "fix": "KB5073724",
      "url": "https://patchblox.com/security/fix/microsoft/kb5073724",
      "released": "2026-01-13T00:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows 10 Version 22H2 for x64-based Systems",
      "fixedVersion": "",
      "fix": "KB5073724",
      "url": "https://patchblox.com/security/fix/microsoft/kb5073724",
      "released": "2026-01-13T00:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows 11 Version 23H2 for ARM64-based Systems",
      "fixedVersion": "22631.6491",
      "fix": "KB5073455",
      "url": "https://patchblox.com/security/fix/microsoft/kb5073455",
      "released": "2026-01-13T00:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows 11 Version 23H2 for x64-based Systems",
      "fixedVersion": "22631.6491",
      "fix": "KB5073455",
      "url": "https://patchblox.com/security/fix/microsoft/kb5073455",
      "released": "2026-01-13T00:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows 11 Version 24H2 for ARM64-based Systems",
      "fixedVersion": "",
      "fix": "KB5074109",
      "url": "https://patchblox.com/security/fix/microsoft/kb5074109",
      "released": "2026-01-13T00:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows 11 Version 24H2 for x64-based Systems",
      "fixedVersion": "",
      "fix": "KB5074109",
      "url": "https://patchblox.com/security/fix/microsoft/kb5074109",
      "released": "2026-01-13T00:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows 11 Version 25H2 for ARM64-based Systems",
      "fixedVersion": "",
      "fix": "KB5074109",
      "url": "https://patchblox.com/security/fix/microsoft/kb5074109",
      "released": "2026-01-13T00:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows 11 Version 25H2 for x64-based Systems",
      "fixedVersion": "",
      "fix": "KB5074109",
      "url": "https://patchblox.com/security/fix/microsoft/kb5074109",
      "released": "2026-01-13T00:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows Server 2012",
      "fixedVersion": "",
      "fix": "KB5073698",
      "url": "https://patchblox.com/security/fix/microsoft/kb5073698",
      "released": "2026-01-13T08:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows Server 2012 (Server Core installation)",
      "fixedVersion": "",
      "fix": "KB5073698",
      "url": "https://patchblox.com/security/fix/microsoft/kb5073698",
      "released": "2026-01-13T08:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows Server 2012 R2",
      "fixedVersion": "",
      "fix": "KB5073696",
      "url": "https://patchblox.com/security/fix/microsoft/kb5073696",
      "released": "2026-01-13T08:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows Server 2012 R2 (Server Core installation)",
      "fixedVersion": "",
      "fix": "KB5073696",
      "url": "https://patchblox.com/security/fix/microsoft/kb5073696",
      "released": "2026-01-13T08:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows Server 2016",
      "fixedVersion": "14393.8783",
      "fix": "KB5073722",
      "url": "https://patchblox.com/security/fix/microsoft/kb5073722",
      "released": "2026-01-13T00:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows Server 2016 (Server Core installation)",
      "fixedVersion": "14393.8783",
      "fix": "KB5073722",
      "url": "https://patchblox.com/security/fix/microsoft/kb5073722",
      "released": "2026-01-13T00:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows Server 2019",
      "fixedVersion": "17763.8276",
      "fix": "KB5073723",
      "url": "https://patchblox.com/security/fix/microsoft/kb5073723",
      "released": "2026-01-13T00:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows Server 2019 (Server Core installation)",
      "fixedVersion": "17763.8276",
      "fix": "KB5073723",
      "url": "https://patchblox.com/security/fix/microsoft/kb5073723",
      "released": "2026-01-13T00:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows Server 2022",
      "fixedVersion": "20348.4648",
      "fix": "KB5073457",
      "url": "https://patchblox.com/security/fix/microsoft/kb5073457",
      "released": "2026-01-13T00:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows Server 2022 (Server Core installation)",
      "fixedVersion": "20348.4648",
      "fix": "KB5073457",
      "url": "https://patchblox.com/security/fix/microsoft/kb5073457",
      "released": "2026-01-13T00:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows Server 2022, 23H2 Edition (Server Core installation)",
      "fixedVersion": "25398.2092",
      "fix": "KB5073450",
      "url": "https://patchblox.com/security/fix/microsoft/kb5073450",
      "released": "2026-01-13T00:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows Server 2025",
      "fixedVersion": "26100.32230",
      "fix": "KB5073379",
      "url": "https://patchblox.com/security/fix/microsoft/kb5073379",
      "released": "2026-01-13T00:00:00Z"
    },
    {
      "platform": "microsoft",
      "product": "Windows Server 2025 (Server Core installation)",
      "fixedVersion": "26100.32230",
      "fix": "KB5073379",
      "url": "https://patchblox.com/security/fix/microsoft/kb5073379",
      "released": "2026-01-13T00:00:00Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-08T19:12:23Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}