{
  "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-2026-56865",
    "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2026-56865",
    "idYear": 2026,
    "status": "PUBLISHED",
    "publishedAt": "2026-08-13T21:58:53.475Z",
    "updatedAt": "2026-08-14T15:34:17.235Z",
    "importedAt": "2026-10-24T01:58:20.586Z",
    "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": "Fix transparency log tile verification bypass in golang.org/x/mod/sumdb/tlog",
      "summary": "A malicious GOPROXY was previously capable of forging up to two sumdb tiles that allow for a requested module to bypass the GOSUMDB check and persist attacker-controlled module content to a local Go module cache. This attack allows for a malicious GOPROXY to serve malicious module content that cannot be detected by evaluating the transparency log. All tiles are now correctly verified against their parents. In order to determine if you have been affected:   rm -r go.sum go.work.sum vendor/ && go mod tidy",
      "affected": [
        {
          "vendor": "Go toolchain",
          "product": "cmd/go",
          "packageName": "cmd/go",
          "collectionURL": "https://pkg.go.dev",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "0",
              "status": "affected",
              "versionType": "semver",
              "lessThan": "1.25.13"
            },
            {
              "version": "1.26.0-0",
              "status": "affected",
              "versionType": "semver",
              "lessThan": "1.26.6"
            },
            {
              "version": "1.27.0-0",
              "status": "affected",
              "versionType": "semver",
              "lessThan": "1.27.0-rc.3"
            }
          ]
        },
        {
          "vendor": "golang.org/x/mod",
          "product": "golang.org/x/mod/sumdb/tlog",
          "packageName": "golang.org/x/mod/sumdb/tlog",
          "collectionURL": "https://pkg.go.dev",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "0",
              "status": "affected",
              "versionType": "semver",
              "lessThan": "0.40.0"
            }
          ]
        }
      ]
    }
  }
}