{"dataType": "CVE_RECORD", "cveMetadata": {"state": "PUBLISHED", "cveId": "CVE-2026-48691", "assignerOrgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca", "assignerShortName": "mitre", "dateUpdated": "2026-05-26T15:45:19.798Z", "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"}]}]}}, "dataVersion": "5.2"}

{}

{"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."}], "id": "CVE-2026-48691", "lastModified": "2026-05-26T17:16:53.670", "metrics": {}, "published": "2026-05-26T17:16:53.670", "references": [{"source": "cve@mitre.org", "url": "https://github.com/pavel-odintsov/fastnetmon"}, {"source": "cve@mitre.org", "url": "https://github.com/pavel-odintsov/fastnetmon/blob/master/src/bgp_protocol.hpp"}, {"source": "cve@mitre.org", "url": "https://lorikeetsecurity.com/blog/fastnetmon-cve-2026-48691-bgp-as-path-overflow"}], "sourceIdentifier": "cve@mitre.org", "vulnStatus": "Received"}

{}

{}