CVE-2026-71271

{
  "id": "CVE-2026-71271",
  "sourceIdentifier": "309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c",
  "published": "2026-08-05T13:24:51.447",
  "lastModified": "2026-10-24T15:10:00.190",
  "vulnStatus": "Deferred",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Memos' webhook URL validation, isReservedIP (internal/webhook/validate.go), checks a candidate IP against a reservedCIDRs list that omits 0.0.0.0/8 and never calls ip.IsUnspecified — unlike the correctly implemented sibling function isInternalIP in internal/httpgetter/html_meta.go, which does."
    },
    {
      "lang": "es",
      "value": "La validación de URL de webhook de Memos, isReservedIP() (internal/webhook/validate.go), comprueba una IP candidata contra una lista de reservedCIDRs que omite 0.0.0.0/8 y nunca llama a ip.IsUnspecified() - a diferencia de la función hermana correctamente implementada isInternalIP() en internal/httpgetter/html_meta.go, que sí lo hace. Debido a que Linux redirige las conexiones a 0.0.0.0 a loopback (127.0.0.1), un atacante que registra una URL de webhook de http://0.0.0.0:PORT/ omite la comprobación de IP reservada y hace que el servidor de Memos realice solicitudes HTTP salientes a su propia interfaz de loopback, exponiendo servicios solo internos."
    }
  ],
  "affected": [
    {
      "source": "309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c",
      "affectedData": [
        {
          "vendor": "usememos",
          "product": "memos",
          "defaultStatus": "unaffected",
          "programFiles": [
            "internal/webhook/validate.go"
          ],
          "versions": [
            {
              "version": "0",
              "lessThanOrEqual": "0.29.1",
              "versionType": "semver",
              "status": "affected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c",
        "type": "Secondary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N",
          "baseScore": 8.5,
          "baseSeverity": "HIGH",
          "attackVector": "NETWORK",
          "attackComplexity": "LOW",
          "privilegesRequired": "LOW",
          "userInteraction": "NONE",
          "scope": "CHANGED",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "LOW",
          "availabilityImpact": "NONE"
        },
        "exploitabilityScore": 3.1,
        "impactScore": 4.7
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-08-05T15:38:03.435461Z",
          "id": "CVE-2026-71271",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c",
      "type": "Secondary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-918"
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://github.com/usememos/memos",
      "source": "309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c"
    },
    {
      "url": "https://github.com/usememos/memos/blob/main/internal/webhook/validate.go",
      "source": "309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c"
    }
  ]
}