{"api_version":"1","generated_at":"2026-05-27T21:47:41+00:00","cve":"CVE-2026-48691","urls":{"html":"https://cve.report/CVE-2026-48691","api":"https://cve.report/api/cve/CVE-2026-48691.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-48691","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-48691"},"summary":{"title":"CVE-2026-48691","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.","state":"PUBLISHED","assigner":"mitre","published_at":"2026-05-26 17:16:53","updated_at":"2026-05-27 21:16:19"},"problem_types":["CWE-190","CWE-122","n/a","CWE-190 CWE-190 Integer Overflow or Wraparound","CWE-122 CWE-122 Heap-based Buffer Overflow"],"metrics":[{"version":"3.1","source":"nvd@nist.gov","type":"Primary","score":"9.8","severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","baseScore":9.8,"baseSeverity":"CRITICAL","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"}},{"version":"3.1","source":"ADP","type":"DECLARED","score":"7.3","severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L","data":{"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"}},{"version":"3.1","source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","type":"Secondary","score":"7.3","severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L","baseScore":7.3,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"LOW","integrityImpact":"LOW","availabilityImpact":"LOW"}}],"references":[{"url":"https://github.com/pavel-odintsov/fastnetmon/blob/master/src/bgp_protocol.hpp","name":"https://github.com/pavel-odintsov/fastnetmon/blob/master/src/bgp_protocol.hpp","refsource":"cve@mitre.org","tags":["Product"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://github.com/pavel-odintsov/fastnetmon","name":"https://github.com/pavel-odintsov/fastnetmon","refsource":"cve@mitre.org","tags":["Product"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://lorikeetsecurity.com/blog/fastnetmon-cve-2026-48691-bgp-as-path-overflow","name":"https://lorikeetsecurity.com/blog/fastnetmon-cve-2026-48691-bgp-as-path-overflow","refsource":"cve@mitre.org","tags":["Third Party Advisory"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-48691","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-48691","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"n/a","product":"n/a","version":"affected n/a","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[{"cve_year":"2026","cve_id":"48691","vulnerable":"1","versionEndIncluding":"1.2.9","cpe1":"cpe","cpe2":"2.3","cpe3":"a","cpe4":"pavel-odintsov","cpe5":"fastnetmon","cpe6":"*","cpe7":"*","cpe8":"*","cpe9":"*","cpe10":"community","cpe11":"*","cpe12":"*","cpe13":"*"}],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"adp":[{"metrics":[{"cvssV3_1":{"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"}},{"other":{"content":{"id":"CVE-2026-48691","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","timestamp":"2026-05-27T20:37:39.723368Z","version":"2.0.3"},"type":"ssvc"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-190","description":"CWE-190 Integer Overflow or Wraparound","lang":"en","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-122","description":"CWE-122 Heap-based Buffer Overflow","lang":"en","type":"CWE"}]}],"providerMetadata":{"dateUpdated":"2026-05-27T20:37:43.097Z","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP"},"title":"CISA ADP Vulnrichment"}],"cna":{"affected":[{"product":"n/a","vendor":"n/a","versions":[{"status":"affected","version":"n/a"}]}],"descriptions":[{"lang":"en","value":"FastNetMon Community Edition through 1.2.9 contains an integer overflow in the BGP AS_PATH attribute encoder. 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