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CVE-2026-78667

Status: Awaiting AnalysisHigh (7.5)—

When parsing a Range header containing a large number of small ranges, FileServer(FS), ServeContent, and ServeFile(FS) can consume an excessive amount of CPU.

CVSS

Exploitation probability (EPSS)

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

🎯 ATT&CK techniques

How this vulnerability is exploited and what the attacker gains, in MITRE ATT&CK terms.

AV:N/PR:N/UI:N indica exposición en red sin autenticación. CWE-770 (asignación excesiva de recursos) en FileServer de Go causa consumo de CPU por Range headers malformados, encajando en DoS de aplicación web.

Inferred by our analysis agent from the official description, CVSS vector and CWE, and checked by a supervisor. May contain errors.

🛡️ ATT&CK mitigations that cover these techniques

Filter Network TrafficVulnerability ScanningPrivileged Account ManagementNetwork SegmentationLimit Access to Resource Over NetworkApplication Isolation and Sandboxing

Affected technologies (1)

⚠ AI-inferred from the description — NVD hasn't analyzed this CVE yet, these aren't verified CPEs.

Golang — GOAI

CWEs

References

Raw JSON (NVD)

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{
  "id": "CVE-2026-78667",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-78667",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-10-09T16:12:49.383383Z"
        }
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.5,
          "attackVector": "NETWORK",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 3.6,
        "exploitabilityScore": 3.9
      }
    ]
  },
  "affected": [
    {
      "source": "security@golang.org",
      "affectedData": [
        {
          "vendor": "Go standard library",
          "product": "net/http",
          "versions": [
            {
              "status": "affected",
              "version": "0",
              "lessThan": "1.26.9",
              "versionType": "semver"
            },
            {
              "status": "affected",
              "version": "1.27.0-0",
              "lessThan": "1.27.2",
              "versionType": "semver"
            }
          ],
          "packageName": "net/http",
          "collectionURL": "https://pkg.go.dev",
          "defaultStatus": "unaffected",
          "programRoutines": [
            {
              "name": "parseRange"
            },
            {
              "name": "ServeContent"
            },
            {
              "name": "ServeFile"
            },
            {
              "name": "ServeFileFS"
            },
            {
              "name": "fileHandler.ServeHTTP"
            },
            {
              "name": "fileTransport.RoundTrip"
            }
          ]
        }
      ]
    }
  ],
  "published": "2026-10-08T23:17:03.880",
  "references": [
    {
      "url": "https://go.dev/cl/847309",
      "source": "security@golang.org"
    },
    {
      "url": "https://go.dev/issue/81858",
      "source": "security@golang.org"
    },
    {
      "url": "https://groups.google.com/g/golang-announce/c/U2fTuyDJznI",
      "source": "security@golang.org"
    },
    {
      "url": "https://pkg.go.dev/vuln/GO-2026-6609",
      "source": "security@golang.org"
    }
  ],
  "vulnStatus": "Awaiting Analysis",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "description": [
        {
          "lang": "en",
          "value": "CWE-770"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "When parsing a Range header containing a large number of small ranges, FileServer(FS), ServeContent, and ServeFile(FS) can consume an excessive amount of CPU."
    }
  ],
  "lastModified": "2026-10-09T17:16:49.690",
  "sourceIdentifier": "security@golang.org"
}