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CVE-2020-12883

Estado: ModificadaCrítica (9.1)—

Buffer over-reads were discovered in the CoAP library in Arm Mbed OS 5.15.3. The CoAP parser is responsible for parsing received CoAP packets. The function sn_coap_parser_options_parse() parses CoAP input linearly using a while loop. Once an option is parsed in a loop, the current point (*packet_data_pptr) is increased correspondingly. The pointer is restricted by the size of the received buffer, as well as by the option delta and option length bytes.

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The actual input packet length is not verified against the number of bytes read when processing the option extended delta and the option extended length. Moreover, the calculation of the message_left variable, in the case of non-extended option deltas, is incorrect and indicates more data left for processing than provided in the function input. All of these lead to heap-based or stack-based memory location read access that is outside of the intended boundary of the buffer. Depending on the platform-specific memory management mechanisms, it can lead to processing of unintended inputs or system memory access violation errors.

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)

ARM — Mbed OS

CWE

Referencias

JSON original (NVD)

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  "id": "CVE-2020-12883",
  "cveTags": [],
  "metrics": {
    "cvssMetricV2": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
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          "baseScore": 6.4,
          "accessVector": "NETWORK",
          "vectorString": "AV:N/AC:L/Au:N/C:P/I:N/A:P",
          "authentication": "NONE",
          "integrityImpact": "NONE",
          "accessComplexity": "LOW",
          "availabilityImpact": "PARTIAL",
          "confidentialityImpact": "PARTIAL"
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          "baseSeverity": "CRITICAL",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
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  "published": "2020-06-18T19:15:09.893",
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      "url": "https://github.com/ARMmbed/mbed-coap/pull/116",
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  "vulnStatus": "Modified",
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      "description": [
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      "lang": "en",
      "value": "Buffer over-reads were discovered in the CoAP library in Arm Mbed OS 5.15.3. The CoAP parser is responsible for parsing received CoAP packets. The function sn_coap_parser_options_parse() parses CoAP input linearly using a while loop. Once an option is parsed in a loop, the current point (*packet_data_pptr) is increased correspondingly. The pointer is restricted by the size of the received buffer, as well as by the option delta and option length bytes. The actual input packet length is not verified against the number of bytes read when processing the option extended delta and the option extended length. Moreover, the calculation of the message_left variable, in the case of non-extended option deltas, is incorrect and indicates more data left for processing than provided in the function input. All of these lead to heap-based or stack-based memory location read access that is outside of the intended boundary of the buffer. Depending on the platform-specific memory management mechanisms, it can lead to processing of unintended inputs or system memory access violation errors."
    },
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      "lang": "es",
      "value": "Se detectaron lecturas excesivas del búfer en la biblioteca CoAP en Arm Mbed OS versión 5.15.3. El analizador CoAP es responsable de analizar los paquetes CoAP recibidos. La función sn_coap_parser_options_parse() analiza la entrada CoAP linealmente usando un bucle while. Una vez que se analiza una opción en un bucle, el punto actual (*packet_data_pptr) se incrementa correspondientemente. El puntero es restringido por el tamaño del búfer recibido, así como por los bytes option delta y option length. La longitud real del paquete de entrada no es comprobada con el número de bytes leídos cuando se procesa la opción delta extendida y la opción longitud extendida. Además, el cálculo de la variable message_left, en el caso de deltas de opción no extendida, es incorrecto e indica que quedan más datos para procesar que los proporcionados en la entrada de la función. Todo esto conlleva a un acceso de lectura de ubicación de memoria en la región heap o stack que está fuera del límite previsto del búfer. Dependiendo de los mecanismos de administración de memoria específicos de la plataforma, puede conllevar al procesamiento de entradas no deseadas o errores de violación de acceso de la memoria de sistema"
    }
  ],
  "lastModified": "2026-06-17T02:52:28.933",
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