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CVE-2024-23185

Estado: AplazadaAlta (7.5)—

Very large headers can cause resource exhaustion when parsing message. The message-parser normally reads reasonably sized chunks of the message. However, when it feeds them to message-header-parser, it starts building up "full_value" buffer out of the smaller chunks. The full_value buffer has no size limit, so large headers can cause large memory usage. It doesn't matter whether it's a single long header line, or a single header split into multiple lines. This bug exists in all Dovecot versions.

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Incoming mails typically have some size limits set by MTA, so even largest possible header size may still fit into Dovecot's vsz_limit. So attackers probably can't DoS a victim user this way. A user could APPEND larger mails though, allowing them to DoS themselves (although maybe cause some memory issues for the backend in general). One can implement restrictions on headers on MTA component preceding Dovecot. No publicly available exploits are known.

CVSS

Probabilidad de explotación (EPSS)

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

Tecnologías afectadas (1)

⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.

Dovecot — DovecotAI

CWE

Referencias

JSON original (NVD)

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{
  "id": "CVE-2024-23185",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2024-23185",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2024-09-10T19:14:08.131462Z"
        }
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "security@open-xchange.com",
        "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@open-xchange.com",
      "affectedData": [
        {
          "vendor": "Open-Xchange GmbH",
          "modules": [
            "core"
          ],
          "product": "OX Dovecot Pro",
          "versions": [
            {
              "status": "affected",
              "version": "0",
              "versionType": "semver",
              "lessThanOrEqual": "2.3.21"
            }
          ],
          "defaultStatus": "unaffected"
        }
      ]
    },
    {
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "affectedData": [
        {
          "cpes": [
            "cpe:2.3:a:open-xchange:ox_dovecot_pro:*:*:*:*:*:*:*:*"
          ],
          "vendor": "open-xchange",
          "product": "ox_dovecot_pro",
          "versions": [
            {
              "status": "affected",
              "version": "0",
              "versionType": "custom",
              "lessThanOrEqual": "2.3.21"
            }
          ],
          "defaultStatus": "unknown"
        }
      ]
    }
  ],
  "published": "2024-09-10T15:15:14.967",
  "references": [
    {
      "url": "https://documentation.open-xchange.com/dovecot/security/advisories/csaf/2024/oxdc-adv-2024-0003.json",
      "source": "security@open-xchange.com"
    },
    {
      "url": "http://seclists.org/fulldisclosure/2024/Aug/18",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "http://www.openwall.com/lists/oss-security/2024/08/15/4",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://lists.debian.org/debian-lts-announce/2024/09/msg00002.html",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    }
  ],
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "security@open-xchange.com",
      "description": [
        {
          "lang": "en",
          "value": "CWE-770"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "Very large headers can cause resource exhaustion when parsing message. The message-parser normally reads reasonably sized chunks of the message. However, when it feeds them to message-header-parser, it starts building up \"full_value\" buffer out of the smaller chunks. The full_value buffer has no size limit, so large headers can cause large memory usage. It doesn't matter whether it's a single long header line, or a single header split into multiple lines. This bug exists in all Dovecot versions. Incoming mails typically have some size limits set by MTA, so even largest possible header size may still fit into Dovecot's vsz_limit. So attackers probably can't DoS a victim user this way. A user could APPEND larger mails though, allowing them to DoS themselves (although maybe cause some memory issues for the backend in general). One can implement restrictions on headers on MTA component preceding Dovecot. No publicly available exploits are known."
    },
    {
      "lang": "es",
      "value": "Los encabezados muy grandes pueden causar el agotamiento de los recursos al analizar el mensaje. El analizador de mensajes normalmente lee fragmentos de tamaño razonable del mensaje. Sin embargo, cuando los envía al analizador de encabezados de mensajes, comienza a construir un búfer de \"valor completo\" a partir de los fragmentos más pequeños. El búfer de valor completo no tiene límite de tamaño, por lo que los encabezados grandes pueden causar un gran uso de memoria. No importa si se trata de una sola línea de encabezado larga o de un solo encabezado dividido en varias líneas. Este error existe en todas las versiones de Dovecot. Los correos entrantes normalmente tienen algunos límites de tamaño establecidos por el MTA, por lo que incluso el tamaño de encabezado más grande posible puede caber en el vsz_limit de Dovecot. Por lo tanto, los atacantes probablemente no puedan atacar a un usuario víctima de esta manera. Sin embargo, un usuario podría ANEXAR correos más grandes, lo que le permitiría atacarse a sí mismo (aunque tal vez cause algunos problemas de memoria para el backend en general). Se pueden implementar restricciones en los encabezados en el componente MTA anterior a Dovecot. No se conocen exploits disponibles públicamente."
    }
  ],
  "lastModified": "2026-06-17T07:12:15.523",
  "sourceIdentifier": "security@open-xchange.com"
}