{"id":"CVE-2026-48691","state":"PUBLISHED","title":"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() fun","description":"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.","publishedAt":"2026-05-26T00:00:00.000Z","updatedAt":"2026-05-27T20:37:43.097Z","severity":{"score":7.3,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L","source":"CISA-ADP"},"assigner":"mitre","products":["n/a n/a"],"affected":[{"vendor":"n/a","product":"n/a","versions":[{"version":"n/a","status":"affected"}]}],"references":["https://github.com/pavel-odintsov/fastnetmon","https://github.com/pavel-odintsov/fastnetmon/blob/master/src/bgp_protocol.hpp","https://lorikeetsecurity.com/blog/fastnetmon-cve-2026-48691-bgp-as-path-overflow"],"weaknesses":["CWE-190","CWE-122"],"ingestedAt":"2026-10-29T20:12:07.131Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/48xxx/CVE-2026-48691.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-48691","state":"PUBLISHED","datePublished":"2026-05-26T00:00:00.000Z","dateUpdated":"2026-05-27T20:37:43.097Z","assignerShortName":"mitre","assignerOrgId":"8254265b-2729-46b6-b9e3-3dfca2d5bfca","dateReserved":"2026-05-22T00:00:00.000Z"},"containers":{"cna":{"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"}]}],"providerMetadata":{"shortName":"mitre","orgId":"8254265b-2729-46b6-b9e3-3dfca2d5bfca","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":{"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"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-190","type":"CWE","lang":"en","description":"CWE-190 Integer Overflow or Wraparound"}]},{"descriptions":[{"cweId":"CWE-122","type":"CWE","lang":"en","description":"CWE-122 Heap-based Buffer Overflow"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-05-27T20:37:43.097Z"}}]}}}