{"id":"UBUNTU-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":"2026-06-15T20:15:15.090442434Z","published":"2026-05-26T17:16:00Z","upstream":["CVE-2026-48690"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-48690"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-48690"},{"type":"REPORT","url":"https://lorikeetsecurity.com/blog/fastnetmon-cve-2026-48690-packet-storage-integer-overflow"},{"type":"REPORT","url":"https://github.com/pavel-odintsov/fastnetmon/commit/4606af43731055297063177263c0107b82ef8986"},{"type":"REPORT","url":"https://github.com/pavel-odintsov/fastnetmon/pull/1056"},{"type":"REPORT","url":"https://github.com/pavel-odintsov/fastnetmon"},{"type":"REPORT","url":"https://github.com/pavel-odintsov/fastnetmon/blob/master/src/packet_storage.hpp"}],"affected":[{"package":{"name":"fastnetmon","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/fastnetmon?arch=source&distro=bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.1.3+dfsg-3","1.1.3+dfsg-4","1.1.3+dfsg-6build1"],"ecosystem_specific":{"binaries":[{"binary_version":"1.1.3+dfsg-6build1","binary_name":"fastnetmon"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-48690.json"}},{"package":{"name":"fastnetmon","ecosystem":"Ubuntu:Pro:20.04:LTS","purl":"pkg:deb/ubuntu/fastnetmon?arch=source&distro=esm-apps%2Ffocal"},"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"],"ecosystem_specific":{"binaries":[{"binary_name":"fastnetmon","binary_version":"1.1.4-1ubuntu0.1~esm1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-48690.json"}},{"package":{"name":"fastnetmon","ecosystem":"Ubuntu:Pro:24.04:LTS","purl":"pkg:deb/ubuntu/fastnetmon?arch=source&distro=esm-apps%2Fnoble"},"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"],"ecosystem_specific":{"binaries":[{"binary_version":"1.2.6-1ubuntu0.1~esm1","binary_name":"fastnetmon"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-48690.json"}},{"package":{"name":"fastnetmon","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/fastnetmon?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.2.8-1build1","1.2.8-1build2","1.2.8+git20250911-1"],"ecosystem_specific":{"binaries":[{"binary_version":"1.2.8+git20250911-1","binary_name":"fastnetmon"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-48690.json"}},{"package":{"name":"fastnetmon","ecosystem":"Ubuntu:Pro:26.04:LTS","purl":"pkg:deb/ubuntu/fastnetmon?arch=source&distro=esm-apps%2Fresolute"},"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"],"ecosystem_specific":{"binaries":[{"binary_name":"fastnetmon","binary_version":"1.2.8+git20250911-2ubuntu0.1~esm1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-48690.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N"},{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N"},{"type":"Ubuntu","score":"medium"}]}