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CVE-2026-48691

Estado: ModificadaCrítica (9.8)—

FastNetMon Community Edition through 1.2.9 contains an integer overflow in the BGP AS_PATH attribute encoder. In src/bgp_protocol.hpp, the IPv4UnicastAnnounce::get_attributes() function computes attribute_length as 'sizeof(bgp_as_path_segment_element_t) + this->as_path_asns.size() * sizeof(uint32_t)' and stores it in a uint8_t field (line 600-605). Since uint8_t can only hold values 0-255, an AS_PATH containing more than 63 ASNs (2 + 64*4 = 258 > 255) causes silent truncation. The truncated length is used for buffer sizing, while the actual data written is the full untruncated amount, resulting in a heap buffer overflow. Similarly, the path_segment_length field at line 621 is also uint8_t, truncating with more than 255 ASNs.

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).

🎯 Técnicas ATT&CK

Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.

Red sin privilegios (AV:N/PR:N) con confidencialidad/integridad/disponibilidad altas. Overflow en codificador BGP permite RCE. T1499.004 por potencial DoS al corromper procesamiento de rutas.

Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Privileged Account ManagementFilter Network TrafficVulnerability ScanningRestrict Web-Based ContentNetwork SegmentationLimit Software Installation

Tecnologías afectadas (1)

Pavel-odintsov — Fastnetmon

CWE

Referencias

JSON original (NVD)

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  "published": "2026-05-26T17:16:53.670",
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      "value": "FastNetMon Community Edition through 1.2.9 contains an integer overflow in the BGP AS_PATH attribute encoder. In src/bgp_protocol.hpp, the IPv4UnicastAnnounce::get_attributes() function computes attribute_length as 'sizeof(bgp_as_path_segment_element_t) + this->as_path_asns.size() * sizeof(uint32_t)' and stores it in a uint8_t field (line 600-605). Since uint8_t can only hold values 0-255, an AS_PATH containing more than 63 ASNs (2 + 64*4 = 258 > 255) causes silent truncation. The truncated length is used for buffer sizing, while the actual data written is the full untruncated amount, resulting in a heap buffer overflow. Similarly, the path_segment_length field at line 621 is also uint8_t, truncating with more than 255 ASNs."
    },
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      "value": "FastNetMon Community Edition hasta la 1.2.9 contiene un desbordamiento de entero en el codificador del atributo BGP AS_PATH. En src/bgp_protocol.hpp, la función IPv4UnicastAnnounce::get_attributes() calcula attribute_length como 'sizeof(bgp_as_path_segment_element_t) + this - as_path_asns.size() * sizeof(uint32_t)' y lo almacena en un campo uint8_t (línea 600-605). Dado que uint8_t solo puede contener valores de 0-255, un AS_PATH que contenga más de 63 ASNs (2 + 644 = 258 > 255) causa una truncación silenciosa. La longitud truncada se utiliza para el dimensionamiento del búfer, mientras que los datos reales escritos son la cantidad completa sin truncar, lo que resulta en un desbordamiento de búfer de pila. De manera similar, el campo path_segment_length en la línea 621 también es uint8_t, truncando con más de 255 ASNs."
    }
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  "lastModified": "2026-07-24T11:10:00.170",
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