{"id":"CVE-2026-48682","details":"FastNetMon Community Edition through 1.2.9 contains an out-of-bounds read in the IPv4 packet parser. In src/simple_packet_parser_ng.cpp, after validating that the packet contains at least sizeof(ipv4_header_t) bytes (20 bytes), the code advances the local_pointer by '4 * ipv4_header-\u003eget_ihl()' (line 164) without validating that (a) IHL \u003e= 5 (the minimum valid value per RFC 791), or (b) 4 * IHL bytes are actually available in the packet. The IHL field is 4 bits, allowing values 0-15, so the advance can be 0-60 bytes. An IHL value of 15 with only 20 bytes validated causes a 40-byte over-read. An IHL of 0-4 causes the pointer to not advance past the IP header, resulting in the TCP/UDP header being parsed from IP header data (type confusion). This vulnerability is reachable via any packet capture interface.","modified":"2026-08-04T11:30:53.798347399Z","published":"2026-06-02T00:00:00Z","database_specific":{"cna_assigner":"mitre","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/48xxx/CVE-2026-48682.json"},"references":[{"type":"WEB","url":"https://github.com/pavel-odintsov/fastnetmon/blob/master/src/simple_packet_parser_ng.cpp"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/48xxx/CVE-2026-48682.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-48682"},{"type":"PACKAGE","url":"https://github.com/pavel-odintsov/fastnetmon"},{"type":"ARTICLE","url":"https://lorikeetsecurity.com/blog/fastnetmon-cve-2026-48682-ipv4-parser-oob"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/pavel-odintsov/fastnetmon","events":[{"introduced":"0"},{"fixed":"394fbe06d112f9609d3d1cb10d60cbf98347c96a"}],"database_specific":{"extracted_events":[{"introduced":"0"},{"fixed":"1.2.9"}],"source":"DESCRIPTION"}}],"versions":["v1.2.8","v1.2.7","v1.2.6","v1.2.5","v1.2.4","v1.2.3","v1.2.2","v1.2.1","v1.2.0","v1.1.9","v1.1.8","v1.1.7","v1.1.6","v1.1.5","v1.1.4","v1.1.3","v1.1.2","v1.1.0","v1.0.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-48682.json"}}],"schema_version":"1.8.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N"}]}