{
  "schemaVersion": 1,
  "attribution": [
    {
      "source": "CISA Known Exploited Vulnerabilities",
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog",
      "licence": "US government work"
    },
    {
      "source": "GitHub Advisory Database",
      "url": "https://github.com/advisories",
      "licence": "CC BY 4.0"
    },
    {
      "source": "Have I Been Pwned",
      "url": "https://haveibeenpwned.com/",
      "licence": "CC BY 4.0"
    },
    {
      "source": "CVE Program (CVE records)",
      "url": "https://www.cve.org/Legal/TermsOfUse",
      "licence": "CVE Terms of Use",
      "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.",
      "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy."
    },
    {
      "source": "FIRST EPSS",
      "url": "https://www.first.org/epss/",
      "licence": "free to use; FIRST requests attribution"
    }
  ],
  "record": {
    "id": "CVE-2025-38508",
    "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2025-38508",
    "idYear": 2025,
    "status": "PUBLISHED",
    "publishedAt": "2025-08-16T10:54:45.567Z",
    "updatedAt": "2026-08-05T12:02:31.621Z",
    "importedAt": "2026-10-24T01:57:34.152Z",
    "snapshot": {
      "id": "cve_2026-10-24_midnight_baseline",
      "at": "2026-10-24T00:00:00.000Z",
      "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z"
    },
    "facts": {
      "title": "x86/sev: Use TSC_FACTOR for Secure TSC frequency calculation",
      "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\nx86/sev: Use TSC_FACTOR for Secure TSC frequency calculation\n\nWhen using Secure TSC, the GUEST_TSC_FREQ MSR reports a frequency based on\nthe nominal P0 frequency, which deviates slightly (typically ~0.2%) from\nthe actual mean TSC frequency due to clocking parameters.\n\nOver extended VM uptime, this discrepancy accumulates, causing clock skew\nbetween the hypervisor and a SEV-SNP VM, leading to early timer interrupts as\nperceived by the guest.\n\nThe guest kernel relies on the reported nominal frequency for TSC-based\ntimekeeping, while the actual frequency set during SNP_LAUNCH_START may\ndiffer. This mismatch results in inaccurate time calculations, causing the\nguest to perceive hrtimers as firing earlier than expected.\n\nUtilize the TSC_FACTOR from the SEV firmware's secrets page (see \"Secrets\nPage Format\" in the SNP Firmware ABI Specification) to calculate the mean\nTSC frequency, ensuring accurate timekeeping and mitigating clock skew in\nSEV-SNP VMs.\n\nUse early_ioremap_encrypted() to map the secrets page as\nioremap_encrypted() uses kmalloc() which is not available during early TSC\ninitialization and causes a panic.\n\n  [ bp: Drop the silly dummy var:\n    https://lore.kernel.org/r/20250630192726.GBaGLlHl84xIopx4Pt@fat_crate.local ]",
      "affected": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "73bbf3b0fbba9aa27fef07a1fbd837661a863f03",
              "status": "affected",
              "versionType": "git",
              "lessThan": "d0195c42e65805938c9eb507657e7cdf8e1e9522"
            },
            {
              "version": "73bbf3b0fbba9aa27fef07a1fbd837661a863f03",
              "status": "affected",
              "versionType": "git",
              "lessThan": "52e1a03e6cf61ae165f59f41c44394a653a0a788"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "versions": [
            {
              "version": "6.14",
              "status": "affected"
            },
            {
              "version": "0",
              "status": "unaffected",
              "versionType": "semver",
              "lessThan": "6.14"
            },
            {
              "version": "6.15.7",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "6.15.*"
            },
            {
              "version": "6.16",
              "status": "unaffected",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ]
        }
      ]
    }
  }
}