{"id":"DEBIAN-CVE-2026-48690","details":"FastNetMon Community Edition through 1.2.9 contains an integer overflow vulnerability in the packet capture buffer allocation. In src/packet_storage.hpp, the allocate_buffer() function computes memory_size_in_bytes as 'buffer_size_in_packets * (max_captured_packet_size + sizeof(fastnetmon_pcap_pkthdr_t)) + sizeof(fastnetmon_pcap_file_header_t)' using unsigned int (32-bit) arithmetic. With max_captured_packet_size=1500 and sizeof(fastnetmon_pcap_pkthdr_t)=16, each packet requires approximately 1516 bytes. If buffer_size_in_packets exceeds approximately 2,832,542, the multiplication overflows, resulting in a much smaller allocation than expected. Subsequent write_packet() calls then write past the allocated buffer, causing heap corruption. The buffer_size_in_packets value is derived from the ban_details_records_count configuration parameter, which is parsed using atoi() with no overflow checking.","modified":"2026-09-14T17:03:16.034946062Z","published":"2026-05-26T17:16:53.547Z","upstream":["CVE-2026-48690"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2026-48690"}],"affected":[{"package":{"name":"fastnetmon","ecosystem":"Debian:12","purl":"pkg:deb/debian/fastnetmon?arch=source&distro=bookworm"},"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"],"ecosystem_specific":{"urgency":"unimportant"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-48690.json"}},{"package":{"name":"fastnetmon","ecosystem":"Debian:13","purl":"pkg:deb/debian/fastnetmon?arch=source&distro=trixie"},"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"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-48690.json"}},{"package":{"name":"fastnetmon","ecosystem":"Debian:14","purl":"pkg:deb/debian/fastnetmon?arch=source&distro=forky"},"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"],"ecosystem_specific":{"urgency":"unimportant"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-48690.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N"}]}