{"id":"CVE-2026-48689","aliases":["DEBIAN-CVE-2026-48689","EUVD-2026-31956","GHSA-5444-f65m-f3c8","UBUNTU-CVE-2026-48689","USN-8429-1"],"status":"published","title":"FastNetMon Community Edition through 1.2.9 contains an off-by-one heap-based buffer overflow in...","description":"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 \u003e maximum_internal_storage_size + 1)' instead of the correct 'if (offset + length \u003e 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.","severity":{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical","assessor":"primary","from":"nvd"},"epss":{"day":"2026-11-10","score":0.00677,"percentile":0.5258,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-122","CWE-193","CWE-787"],"published":"2026-05-26T00:00:00Z","modified":"2026-10-28T02:30:51Z","fixes":[{"ecosystem":"Debian:13","package":"fastnetmon","fixed_in":["1.2.9-0+deb13u1"],"sources":["osv"]},{"ecosystem":"Debian:14","package":"fastnetmon","fixed_in":["1.2.9-1"],"sources":["osv"]},{"ecosystem":"Ubuntu:Pro:24.04:LTS","package":"fastnetmon","fixed_in":["1.2.6-1ubuntu0.1~esm1"],"sources":["osv"]},{"ecosystem":"Ubuntu:Pro:26.04:LTS","package":"fastnetmon","fixed_in":["1.2.8+git20250911-2ubuntu0.1~esm1"],"sources":["osv"]}],"affected":[{"source":"osv","ecosystem":"Debian:13","package":"fastnetmon","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.2.9-0+deb13u1"}]}],"versions":["1.2.8+git20250911-1","1.2.8+git20250911-2","1.2.8-1"]},{"source":"osv","ecosystem":"Debian:14","package":"fastnetmon","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.2.9-1"}]}],"versions":["1.2.8+git20250911-1","1.2.8+git20250911-2","1.2.8-1"]},{"source":"osv","ecosystem":"Ubuntu:Pro:24.04:LTS","package":"fastnetmon","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.2.6-1ubuntu0.1~esm1"}]}],"versions":["1.2.5-1","1.2.6-1","1.2.6-1build1","1.2.6-1build2","1.2.6-1build3","1.2.6-1build4"]},{"source":"osv","ecosystem":"Ubuntu:25.10","package":"fastnetmon","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.2.8-1build1","1.2.8-1build2","1.2.8+git20250911-1"]},{"source":"osv","ecosystem":"Ubuntu:26.10","package":"fastnetmon","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.2.8+git20250911-2","1.2.9-1","1.2.9-1build1","1.2.9-1build2"]},{"source":"osv","ecosystem":"Ubuntu:Pro:26.04:LTS","package":"fastnetmon","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.2.8+git20250911-2ubuntu0.1~esm1"}]}],"versions":["1.2.8+git20250911-1","1.2.8+git20250911-1build1","1.2.8+git20250911-1build2","1.2.8+git20250911-2"]},{"source":"osv","ecosystem":"Ubuntu:Pro:20.04:LTS","package":"fastnetmon","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.1.4-1ubuntu0.1~esm1"}]}],"versions":["1.1.4-1","1.1.4-1build3","1.1.4-1build4","1.1.4-1build5"],"bundled":5},{"source":"osv","ecosystem":"Ubuntu:Pro:24.04:LTS","package":"fastnetmon","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.2.6-1ubuntu0.1~esm1"}]}],"versions":["1.2.5-1","1.2.6-1","1.2.6-1build1","1.2.6-1build2","1.2.6-1build3","1.2.6-1build4"],"bundled":5},{"source":"osv","ecosystem":"Ubuntu:Pro:26.04:LTS","package":"fastnetmon","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.2.8+git20250911-2ubuntu0.1~esm1"}]}],"versions":["1.2.8+git20250911-1","1.2.8+git20250911-1build1","1.2.8+git20250911-1build2","1.2.8+git20250911-2"],"bundled":5}],"products":[{"vendor":"pavel-odintsov","product":"fastnetmon"}],"references":[{"url":"https://github.com/pavel-odintsov/fastnetmon","tags":["Product","package","report"]},{"url":"https://github.com/pavel-odintsov/fastnetmon/blob/master/src/dynamic_binary_buffer.hpp","tags":["Product","web","report"]},{"url":"https://lorikeetsecurity.com/blog/fastnetmon-cve-2026-48689-dynamic-buffer-off-by-one","tags":["Exploit","Third Party Advisory","article","report"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-48689","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-5444-f65m-f3c8"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/48xxx/CVE-2026-48689.json","tags":["advisory"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2026-48689","tags":["advisory"]},{"url":"https://ubuntu.com/security/CVE-2026-48689","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-48689","tags":["report"]},{"url":"https://github.com/pavel-odintsov/fastnetmon/pull/1051","tags":["report"]},{"url":"https://github.com/pavel-odintsov/fastnetmon/commit/fa80390ed446f887ca6fa39c9e5b6fff8846e822","tags":["report"]},{"url":"https://ubuntu.com/security/notices/USN-8429-1","tags":["advisory"]},{"url":"https://ubuntu.com/security/CVE-2026-48686","tags":["report"]},{"url":"https://ubuntu.com/security/CVE-2026-48687","tags":["report"]},{"url":"https://ubuntu.com/security/CVE-2026-48691","tags":["report"]},{"url":"https://ubuntu.com/security/CVE-2026-48694","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2026-48689","description":"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 \u003e maximum_internal_storage_size + 1)' instead of the correct 'if (offset + length \u003e 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.","status":"published","published":"2026-05-26T00:00:00Z","modified":"2026-05-27T00:20:18.668Z","cvss":[{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical","assessor":"adp"}],"cwes":["CWE-193","CWE-122"],"updated_at":"2026-11-02T13:50:49.872037Z"}],"euvd":[{"id":"EUVD-2026-31956","description":"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 \u003e maximum_internal_storage_size + 1)' instead of the correct 'if (offset + length \u003e 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.","status":"published","published":"2026-05-26T00:00:00Z","modified":"2026-05-27T00:20:18Z","cvss":[{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical"}],"updated_at":"2026-11-02T18:21:06.054612Z"}],"ghsa":[{"id":"GHSA-5444-f65m-f3c8","title":"FastNetMon Community Edition through 1.2.9 contains an off-by-one heap-based buffer overflow in...","description":"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 \u003e maximum_internal_storage_size + 1)' instead of the correct 'if (offset + length \u003e 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.","status":"published","published":"2026-05-26T21:31:58Z","modified":"2026-05-27T03:30:31Z","cvss":[{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical"}],"cwes":["CWE-122","CWE-787"],"updated_at":"2026-11-02T15:08:19.474205Z"}],"nvd":[{"id":"CVE-2026-48689","description":"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 \u003e maximum_internal_storage_size + 1)' instead of the correct 'if (offset + length \u003e 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.","status":"published","published":"2026-05-26T19:16:28.663Z","modified":"2026-07-24T11:10:00.17Z","cvss":[{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical","assessor":"primary"},{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical","assessor":"secondary"}],"cwes":["CWE-787","CWE-122","CWE-193"],"updated_at":"2026-11-02T14:12:20.511562Z"}],"osv":[{"id":"CVE-2026-48689","description":"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 \u003e maximum_internal_storage_size + 1)' instead of the correct 'if (offset + length \u003e 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.","status":"published","published":"2026-05-26T00:00:00Z","modified":"2026-10-28T02:30:51.944753393Z","cvss":[{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical"}],"updated_at":"2026-11-02T15:45:06.701612Z"},{"id":"DEBIAN-CVE-2026-48689","description":"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 \u003e maximum_internal_storage_size + 1)' instead of the correct 'if (offset + length \u003e 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.","status":"published","published":"2026-05-26T19:16:28.663Z","modified":"2026-10-01T03:03:16.461202637Z","cvss":[{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical"}],"updated_at":"2026-11-02T15:45:56.444225Z"},{"id":"UBUNTU-CVE-2026-48689","description":"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 \u003e maximum_internal_storage_size + 1)' instead of the correct 'if (offset + length \u003e 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.","status":"published","published":"2026-05-26T19:16:00Z","modified":"2026-10-17T12:58:30.328974241Z","cvss":[{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical"},{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical"}],"updated_at":"2026-11-02T16:56:33.391918Z"},{"id":"USN-8429-1","title":"fastnetmon vulnerabilities","description":"It was discovered that FastNetMon incorrectly validated prefix lengths when\ndecoding BGP NLRI data. A remote attacker could possibly use this issue to\ncause a denial of service or execute arbitrary code. This issue only\naffected Ubuntu 24.04 LTS and Ubuntu 26.04 LTS. (CVE-2026-48686)\n\nIt was discovered that FastNetMon incorrectly sanitized input in the\nJuniper router integration plugin. An attacker could possibly use this\nissue to execute arbitrary commands. (CVE-2026-48687)\n\nIt was discovered that FastNetMon incorrectly handled buffer bounds checks\nwhen processing network traffic. A remote attacker could possibly use this\nissue to cause a denial of service or execute arbitrary code. This issue\nonly affected Ubuntu 24.04 LTS and Ubuntu 26.04 LTS. (CVE-2026-48689)\n\nIt was discovered that FastNetMon incorrectly handled encoding the BGP\nAS_PATH attribute. A remote attacker could possibly use this issue to cause\na denial of service or execute arbitrary code. This issue only affected\nUbuntu 24.04 LTS and Ubuntu 26.04 LTS. (CVE-2026-48691)\n\nIt was discovered that FastNetMon incorrectly validated IP address input in\nthe Juniper router integration plugin. An attacker could possibly use this\nissue to inject arbitrary router configuration commands. (CVE-2026-48694)","status":"published","published":"2026-06-15T16:11:00Z","modified":"2026-06-16T05:14:18.252687362Z","updated_at":"2026-11-02T16:58:25.103481Z"}]}}