CVE-2026-48691

{"dataType": "CVE_RECORD", "cveMetadata": {"state": "PUBLISHED", "cveId": "CVE-2026-48691", "assignerOrgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca", "assignerShortName": "mitre", "dateUpdated": "2026-05-27T20:37:43.097Z", "dateReserved": "2026-05-22T00:00:00.000Z", "datePublished": "2026-05-26T00:00:00.000Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca", "shortName": "mitre", "dateUpdated": "2026-05-26T15:45:19.798Z"}, "descriptions": [{"lang": "en", "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."}], "affected": [{"vendor": "n/a", "product": "n/a", "versions": [{"version": "n/a", "status": "affected"}]}], "references": [{"url": "https://github.com/pavel-odintsov/fastnetmon"}, {"url": "https://github.com/pavel-odintsov/fastnetmon/blob/master/src/bgp_protocol.hpp"}, {"url": "https://lorikeetsecurity.com/blog/fastnetmon-cve-2026-48691-bgp-as-path-overflow"}], "problemTypes": [{"descriptions": [{"type": "text", "lang": "en", "description": "n/a"}]}]}, "adp": [{"problemTypes": [{"descriptions": [{"type": "CWE", "cweId": "CWE-190", "lang": "en", "description": "CWE-190 Integer Overflow or Wraparound"}]}, {"descriptions": [{"type": "CWE", "cweId": "CWE-122", "lang": "en", "description": "CWE-122 Heap-based Buffer Overflow"}]}], "metrics": [{"cvssV3_1": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.3, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L", "integrityImpact": "LOW", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "LOW", "privilegesRequired": "NONE", "confidentialityImpact": "LOW"}}, {"other": {"type": "ssvc", "content": {"timestamp": "2026-05-27T20:37:39.723368Z", "id": "CVE-2026-48691", "options": [{"Exploitation": "none"}, {"Automatable": "yes"}, {"Technical Impact": "partial"}], "role": "CISA Coordinator", "version": "2.0.3"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-05-27T20:37:43.097Z"}}]}, "dataVersion": "5.2"}

{"dataType": "CVE_RECORD", "containers": {"cna": {"affected": [{"vendor": "n/a", "product": "n/a", "versions": [{"status": "affected", "version": "n/a"}]}], "references": [{"url": "https://github.com/pavel-odintsov/fastnetmon"}, {"url": "https://github.com/pavel-odintsov/fastnetmon/blob/master/src/bgp_protocol.hpp"}, {"url": "https://lorikeetsecurity.com/blog/fastnetmon-cve-2026-48691-bgp-as-path-overflow"}], "descriptions": [{"lang": "en", "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."}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "text", "description": "n/a"}]}], "providerMetadata": {"orgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca", "shortName": "mitre", "dateUpdated": "2026-05-26T15:45:19.798Z"}}, "adp": [{"title": "CISA ADP Vulnrichment", "metrics": [{"cvssV3_1": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.3, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L", "integrityImpact": "LOW", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "LOW", "privilegesRequired": "NONE", "confidentialityImpact": "LOW"}}, {"other": {"type": "ssvc", "content": {"id": "CVE-2026-48691", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "yes"}, {"Technical Impact": "partial"}], "version": "2.0.3", "timestamp": "2026-05-27T20:37:39.723368Z"}}}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "cweId": "CWE-190", "description": "CWE-190 Integer Overflow or Wraparound"}]}, {"descriptions": [{"lang": "en", "type": "CWE", "cweId": "CWE-122", "description": "CWE-122 Heap-based Buffer Overflow"}]}], "providerMetadata": {"shortName": "CISA-ADP", "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "dateUpdated": "2026-05-27T20:34:54.076Z"}}]}, "cveMetadata": {"cveId": "CVE-2026-48691", "state": "PUBLISHED", "dateUpdated": "2026-05-26T15:45:19.798Z", "dateReserved": "2026-05-22T00:00:00.000Z", "assignerOrgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca", "datePublished": "2026-05-26T00:00:00.000Z", "assignerShortName": "mitre"}, "dataVersion": "5.2"}

{"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 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."}, {"lang": "es", "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 funci\u00f3n 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 (l\u00ednea 600-605). Dado que uint8_t solo puede contener valores de 0-255, un AS_PATH que contenga m\u00e1s de 63 ASNs (2 + 644 = 258 > 255) causa una truncaci\u00f3n silenciosa. La longitud truncada se utiliza para el dimensionamiento del b\u00fafer, mientras que los datos reales escritos son la cantidad completa sin truncar, lo que resulta en un desbordamiento de b\u00fafer de pila. De manera similar, el campo path_segment_length en la l\u00ednea 621 tambi\u00e9n es uint8_t, truncando con m\u00e1s de 255 ASNs."}], "id": "CVE-2026-48691", "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": "LOW", "baseScore": 7.3, "baseSeverity": "HIGH", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 3.4, "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-48691", "options": [{"exploitation": "none"}, {"automatable": "yes"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2026-05-27T20:37:39.723368Z", "version": "2.0.3"}}]}, "published": "2026-05-26T17:16:53.670", "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/bgp_protocol.hpp"}, {"source": "cve@mitre.org", "tags": ["Third Party Advisory"], "url": "https://lorikeetsecurity.com/blog/fastnetmon-cve-2026-48691-bgp-as-path-overflow"}], "sourceIdentifier": "cve@mitre.org", "vulnStatus": "Modified", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-190"}], "source": "nvd@nist.gov", "type": "Primary"}, {"description": [{"lang": "en", "value": "CWE-122"}, {"lang": "en", "value": "CWE-190"}], "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary"}]}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[0,1.2.9]"}}], "enrichment": {"confidence": 80.0, "confidence_source": "inferred", "scores": [{"score": 80.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "n/a", "source": "cna", "vendor": "n/a"}, "product": "fastnetmon", "vendor": "pavel-odintsov"}], "created": "2026-05-26T20:15:14.955362+00:00", "title": "Integer Overflow in FastNetMon BGP AS_PATH Encoder Causes Heap Buffer Overflow", "updated": "2026-05-28T00:00:14.463299+00:00", "vendors": ["pavel-odintsov", "pavel-odintsov$PRODUCT$fastnetmon"]}