CVE-2026-48689

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{"affected": [{"affectedData": [{"product": "n/a", "vendor": "n/a", "versions": [{"status": "affected", "version": "n/a"}]}], "source": "cve@mitre.org"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:pavel-odintsov:fastnetmon:*:*:*:*:community:*:*:*", "matchCriteriaId": "E712A01F-3AD7-4CC2-9A8B-F8C63756EBBF", "versionEndIncluding": "1.2.9", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "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."}, {"lang": "es", "value": "FastNetMon Community Edition hasta la versi\u00f3n 1.2.9 contiene un desbordamiento de b\u00fafer basado en mont\u00edculo por un byte en la clase dynamic_binary_buffer_t (src/dynamic_binary_buffer.hpp). Cinco m\u00e9todos (append_dynamic_buffer, append_data_as_pointer, append_data_as_object_ptr, memcpy_from_ptr, memcpy_from_object_ptr) utilizan una comprobaci\u00f3n de l\u00edmites 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 m\u00e1s all\u00e1 del final del b\u00fafer asignado en el mont\u00edculo. La clase se utiliza de forma generalizada en la codificaci\u00f3n/decodificaci\u00f3n de mensajes BGP, el procesamiento de plantillas NetFlow y la construcci\u00f3n de NLRI de Flow Spec. Un atacante que puede enviar tr\u00e1fico de red (NetFlow, sFlow, IPFIX o BGP) a una instancia de FastNetMon puede desencadenar este desbordamiento, logrando potencialmente ejecuci\u00f3n de c\u00f3digo arbitrario al corromper los metadatos del mont\u00edculo. Cabe destacar que el m\u00e9todo append_byte() utiliza la comprobaci\u00f3n de l\u00edmites correcta, confirmando la inconsistencia."}], "id": "CVE-2026-48689", "lastModified": "2026-07-24T11:10:00.170", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 9.8, "baseSeverity": "CRITICAL", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 5.9, "source": "nvd@nist.gov", "type": "Primary"}, {"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 9.8, "baseSeverity": "CRITICAL", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 5.9, "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-48689", "options": [{"exploitation": "none"}, {"automatable": "yes"}, {"technicalImpact": "total"}], "role": "CISA Coordinator", "timestamp": "2026-05-27T00:20:15.356833Z", "version": "2.0.3"}}]}, "published": "2026-05-26T19:16:28.663", "references": [{"source": "cve@mitre.org", "tags": ["Product"], "url": "https://github.com/pavel-odintsov/fastnetmon"}, {"source": "cve@mitre.org", "tags": ["Product"], "url": "https://github.com/pavel-odintsov/fastnetmon/blob/master/src/dynamic_binary_buffer.hpp"}, {"source": "cve@mitre.org", "tags": ["Exploit", "Third Party Advisory"], "url": "https://lorikeetsecurity.com/blog/fastnetmon-cve-2026-48689-dynamic-buffer-off-by-one"}], "sourceIdentifier": "cve@mitre.org", "vulnStatus": "Modified", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-787"}], "source": "nvd@nist.gov", "type": "Primary"}, {"description": [{"lang": "en", "value": "CWE-122"}, {"lang": "en", "value": "CWE-193"}], "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary"}]}

{}

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