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CVE-2026-48689

Estado: ModificadaCrítica (9.8)—

FastNetMon Community Edition through 1.2.9 contains an off-by-one heap-based buffer overflow in the dynamic_binary_buffer_t class (src/dynamic_binary_buffer.hpp). Five methods (append_dynamic_buffer, append_data_as_pointer, append_data_as_object_ptr, memcpy_from_ptr, memcpy_from_object_ptr) use an incorrect bounds check of the form 'if (offset + length > maximum_internal_storage_size + 1)' instead of the correct 'if (offset + length > maximum_internal_storage_size)'. This allows writing exactly one byte past the end of the heap-allocated buffer.

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The class is used pervasively in BGP message encoding/decoding, NetFlow template processing, and Flow Spec NLRI construction. An attacker who can send network traffic (NetFlow, sFlow, IPFIX, or BGP) to a FastNetMon instance can trigger this overflow, potentially achieving arbitrary code execution by corrupting heap metadata. Notably, the append_byte() method uses the correct bounds check, confirming the inconsistency.

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.

Vector CVSS N/N/N sin interacción: T1190. Buffer overflow remoto en FastNetMon permite code execution (T1059) y potencialmente escalada de privilegios (T1068) al corromper metadatos heap.

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 ManagementVulnerability ScanningRestrict Web-Based ContentNetwork SegmentationLimit Software InstallationLimit Access to Resource Over Network

Tecnologías afectadas (1)

Pavel-odintsov — Fastnetmon

CWE

Referencias

JSON original (NVD)

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      "value": "FastNetMon Community Edition through 1.2.9 contains an off-by-one heap-based buffer overflow in the dynamic_binary_buffer_t class (src/dynamic_binary_buffer.hpp). Five methods (append_dynamic_buffer, append_data_as_pointer, append_data_as_object_ptr, memcpy_from_ptr, memcpy_from_object_ptr) use an incorrect bounds check of the form 'if (offset + length > maximum_internal_storage_size + 1)' instead of the correct 'if (offset + length > maximum_internal_storage_size)'. This allows writing exactly one byte past the end of the heap-allocated buffer. The class is used pervasively in BGP message encoding/decoding, NetFlow template processing, and Flow Spec NLRI construction. An attacker who can send network traffic (NetFlow, sFlow, IPFIX, or BGP) to a FastNetMon instance can trigger this overflow, potentially achieving arbitrary code execution by corrupting heap metadata. Notably, the append_byte() method uses the correct bounds check, confirming the inconsistency."
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      "value": "FastNetMon Community Edition hasta la versión 1.2.9 contiene un desbordamiento de búfer basado en montículo por un byte en la clase dynamic_binary_buffer_t (src/dynamic_binary_buffer.hpp). Cinco métodos (append_dynamic_buffer, append_data_as_pointer, append_data_as_object_ptr, memcpy_from_ptr, memcpy_from_object_ptr) utilizan una comprobación de límites incorrecta de la forma 'if (offset + length > maximum_internal_storage_size + 1)' en lugar de la correcta 'if (offset + length > maximum_internal_storage_size)'. Esto permite escribir exactamente un byte más allá del final del búfer asignado en el montículo. La clase se utiliza de forma generalizada en la codificación/decodificación de mensajes BGP, el procesamiento de plantillas NetFlow y la construcción de NLRI de Flow Spec. Un atacante que puede enviar tráfico de red (NetFlow, sFlow, IPFIX o BGP) a una instancia de FastNetMon puede desencadenar este desbordamiento, logrando potencialmente ejecución de código arbitrario al corromper los metadatos del montículo. Cabe destacar que el método append_byte() utiliza la comprobación de límites correcta, confirmando la inconsistencia."
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