{"id":"CVE-2026-48685","aliases":["DEBIAN-CVE-2026-48685","EUVD-2026-31841","GHSA-4h2g-xxvj-v3w5","UBUNTU-CVE-2026-48685"],"status":"published","title":"FastNetMon Community Edition through 1.2.9 has out-of-bounds memory access because it incorrectly...","description":"FastNetMon Community Edition through 1.2.9 has out-of-bounds memory access because it incorrectly parses BGP path attributes with the extended length flag set. In src/bgp_protocol.hpp, the parse_raw_bgp_attribute() function correctly identifies when extended_length_bit is set and sets length_of_length_field to 2, but then reads only a single byte for the attribute value length (attribute_value_length = value[2] at line 173). Per RFC 4271 Section 4.3, when the Extended Length bit is set, the Attribute Length field is two octets and the value should be read as a 16-bit big-endian integer from value[2] and value[3]. As a result, any attribute longer than 255 bytes has its length silently truncated to the low byte (e.g., 300 bytes = 0x012C is read as 0x2C = 44 bytes). The remaining 256 bytes are then misinterpreted as subsequent attributes, causing cascading parse failures and potential out-of-bounds memory access.","severity":{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"primary","from":"nvd"},"epss":{"day":"2026-11-10","score":0.00295,"percentile":0.22375,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-130"],"published":"2026-05-26T00:00:00Z","modified":"2026-10-28T02:30:47Z","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"]}],"affected":[{"source":"osv","ecosystem":"Debian:12","package":"fastnetmon","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.2.4-2","1.2.4-2+deb12u1","1.2.5-1","1.2.5-2","1.2.5-2~bpo12+1","1.2.6-1","1.2.6-1~bpo12+1","1.2.7-1","1.2.7-1~bpo12+1","1.2.8+git20250911-1","1.2.8+git20250911-2","1.2.8-1","1.2.8-1~bpo12+1","1.2.9-1"]},{"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:18.04:LTS","package":"fastnetmon","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.1.3+dfsg-3","1.1.3+dfsg-4","1.1.3+dfsg-6build1"]},{"source":"osv","ecosystem":"Ubuntu:Pro:20.04:LTS","package":"fastnetmon","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.1.4-1","1.1.4-1build3","1.1.4-1build4","1.1.4-1build5","1.1.4-1ubuntu0.1~esm1"]},{"source":"osv","ecosystem":"Ubuntu:Pro:24.04:LTS","package":"fastnetmon","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"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","1.2.6-1ubuntu0.1~esm1"]},{"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"}]}],"versions":["1.2.8+git20250911-1","1.2.8+git20250911-1build1","1.2.8+git20250911-1build2","1.2.8+git20250911-2","1.2.8+git20250911-2ubuntu0.1~esm1"]}],"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/bgp_protocol.hpp","tags":["Product","web","report"]},{"url":"https://lorikeetsecurity.com/blog/fastnetmon-cve-2026-48685-bgp-extended-length","tags":["Third Party Advisory","article","report"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-48685","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-4h2g-xxvj-v3w5"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/48xxx/CVE-2026-48685.json","tags":["advisory"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2026-48685","tags":["advisory"]},{"url":"https://ubuntu.com/security/CVE-2026-48685","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-48685","tags":["report"]},{"url":"https://github.com/pavel-odintsov/fastnetmon/commit/2bf813b2590b9847308877a65fc72df560dd282f","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2026-48685","description":"FastNetMon Community Edition through 1.2.9 has out-of-bounds memory access because it incorrectly parses BGP path attributes with the extended length flag set. In src/bgp_protocol.hpp, the parse_raw_bgp_attribute() function correctly identifies when extended_length_bit is set and sets length_of_length_field to 2, but then reads only a single byte for the attribute value length (attribute_value_length = value[2] at line 173). Per RFC 4271 Section 4.3, when the Extended Length bit is set, the Attribute Length field is two octets and the value should be read as a 16-bit big-endian integer from value[2] and value[3]. As a result, any attribute longer than 255 bytes has its length silently truncated to the low byte (e.g., 300 bytes = 0x012C is read as 0x2C = 44 bytes). The remaining 256 bytes are then misinterpreted as subsequent attributes, causing cascading parse failures and potential out-of-bounds memory access.","status":"published","published":"2026-05-26T00:00:00Z","modified":"2026-05-26T20:56:12.251Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"adp"}],"cwes":["CWE-130"],"updated_at":"2026-11-02T14:19:47.998488Z"}],"euvd":[{"id":"EUVD-2026-31841","description":"FastNetMon Community Edition through 1.2.9 has out-of-bounds memory access because it incorrectly parses BGP path attributes with the extended length flag set. In src/bgp_protocol.hpp, the parse_raw_bgp_attribute() function correctly identifies when extended_length_bit is set and sets length_of_length_field to 2, but then reads only a single byte for the attribute value length (attribute_value_length = value[2] at line 173). Per RFC 4271 Section 4.3, when the Extended Length bit is set, the Attribute Length field is two octets and the value should be read as a 16-bit big-endian integer from value[2] and value[3]. As a result, any attribute longer than 255 bytes has its length silently truncated to the low byte (e.g., 300 bytes = 0x012C is read as 0x2C = 44 bytes). The remaining 256 bytes are then misinterpreted as subsequent attributes, causing cascading parse failures and potential out-of-bounds memory access.","status":"published","published":"2026-05-26T00:00:00Z","modified":"2026-05-26T20:56:12Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-02T18:21:06.423934Z"}],"ghsa":[{"id":"GHSA-4h2g-xxvj-v3w5","title":"FastNetMon Community Edition through 1.2.9 has out-of-bounds memory access because it incorrectly...","description":"FastNetMon Community Edition through 1.2.9 has out-of-bounds memory access because it incorrectly parses BGP path attributes with the extended length flag set. In src/bgp_protocol.hpp, the parse_raw_bgp_attribute() function correctly identifies when extended_length_bit is set and sets length_of_length_field to 2, but then reads only a single byte for the attribute value length (attribute_value_length = value[2] at line 173). Per RFC 4271 Section 4.3, when the Extended Length bit is set, the Attribute Length field is two octets and the value should be read as a 16-bit big-endian integer from value[2] and value[3]. As a result, any attribute longer than 255 bytes has its length silently truncated to the low byte (e.g., 300 bytes = 0x012C is read as 0x2C = 44 bytes). The remaining 256 bytes are then misinterpreted as subsequent attributes, causing cascading parse failures and potential out-of-bounds memory access.","status":"published","published":"2026-05-26T18:31:43Z","modified":"2026-05-26T21:32:57Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"cwes":["CWE-130"],"updated_at":"2026-11-02T15:08:18.762226Z"}],"nvd":[{"id":"CVE-2026-48685","description":"FastNetMon Community Edition through 1.2.9 has out-of-bounds memory access because it incorrectly parses BGP path attributes with the extended length flag set. In src/bgp_protocol.hpp, the parse_raw_bgp_attribute() function correctly identifies when extended_length_bit is set and sets length_of_length_field to 2, but then reads only a single byte for the attribute value length (attribute_value_length = value[2] at line 173). Per RFC 4271 Section 4.3, when the Extended Length bit is set, the Attribute Length field is two octets and the value should be read as a 16-bit big-endian integer from value[2] and value[3]. As a result, any attribute longer than 255 bytes has its length silently truncated to the low byte (e.g., 300 bytes = 0x012C is read as 0x2C = 44 bytes). The remaining 256 bytes are then misinterpreted as subsequent attributes, causing cascading parse failures and potential out-of-bounds memory access.","status":"published","published":"2026-05-26T16:16:26.57Z","modified":"2026-07-24T11:10:00.17Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"primary"},{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"secondary"}],"cwes":["CWE-130"],"updated_at":"2026-11-02T14:12:20.131508Z"}],"osv":[{"id":"CVE-2026-48685","description":"FastNetMon Community Edition through 1.2.9 has out-of-bounds memory access because it incorrectly parses BGP path attributes with the extended length flag set. In src/bgp_protocol.hpp, the parse_raw_bgp_attribute() function correctly identifies when extended_length_bit is set and sets length_of_length_field to 2, but then reads only a single byte for the attribute value length (attribute_value_length = value[2] at line 173). Per RFC 4271 Section 4.3, when the Extended Length bit is set, the Attribute Length field is two octets and the value should be read as a 16-bit big-endian integer from value[2] and value[3]. As a result, any attribute longer than 255 bytes has its length silently truncated to the low byte (e.g., 300 bytes = 0x012C is read as 0x2C = 44 bytes). The remaining 256 bytes are then misinterpreted as subsequent attributes, causing cascading parse failures and potential out-of-bounds memory access.","status":"published","published":"2026-05-26T00:00:00Z","modified":"2026-10-28T02:30:47.300176668Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-02T15:45:06.701612Z"},{"id":"DEBIAN-CVE-2026-48685","description":"FastNetMon Community Edition through 1.2.9 has out-of-bounds memory access because it incorrectly parses BGP path attributes with the extended length flag set. In src/bgp_protocol.hpp, the parse_raw_bgp_attribute() function correctly identifies when extended_length_bit is set and sets length_of_length_field to 2, but then reads only a single byte for the attribute value length (attribute_value_length = value[2] at line 173). Per RFC 4271 Section 4.3, when the Extended Length bit is set, the Attribute Length field is two octets and the value should be read as a 16-bit big-endian integer from value[2] and value[3]. As a result, any attribute longer than 255 bytes has its length silently truncated to the low byte (e.g., 300 bytes = 0x012C is read as 0x2C = 44 bytes). The remaining 256 bytes are then misinterpreted as subsequent attributes, causing cascading parse failures and potential out-of-bounds memory access.","status":"published","published":"2026-05-26T16:16:26.57Z","modified":"2026-10-01T03:03:16.507918122Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-02T15:45:56.444225Z"},{"id":"UBUNTU-CVE-2026-48685","description":"FastNetMon Community Edition through 1.2.9 has out-of-bounds memory access because it incorrectly parses BGP path attributes with the extended length flag set. In src/bgp_protocol.hpp, the parse_raw_bgp_attribute() function correctly identifies when extended_length_bit is set and sets length_of_length_field to 2, but then reads only a single byte for the attribute value length (attribute_value_length = value[2] at line 173). Per RFC 4271 Section 4.3, when the Extended Length bit is set, the Attribute Length field is two octets and the value should be read as a 16-bit big-endian integer from value[2] and value[3]. As a result, any attribute longer than 255 bytes has its length silently truncated to the low byte (e.g., 300 bytes = 0x012C is read as 0x2C = 44 bytes). The remaining 256 bytes are then misinterpreted as subsequent attributes, causing cascading parse failures and potential out-of-bounds memory access.","status":"published","published":"2026-05-26T16:16:00Z","modified":"2026-10-17T12:58:32.003861575Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium"},{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-02T16:56:33.391918Z"}]}}