| Name | CVE-2026-48690 |
| Description | 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. |
| Source | CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more) |
| Debian Bugs | 1138646 |
The table below lists information on source packages.
| Source Package | Release | Version | Status |
|---|---|---|---|
| fastnetmon (PTS) | bookworm, bookworm (security) | 1.2.4-2+deb12u1 | vulnerable |
| trixie | 1.2.8-1 | vulnerable | |
| forky, sid | 1.2.9-1 | fixed |
The information below is based on the following data on fixed versions.
| Package | Type | Release | Fixed Version | Urgency | Origin | Debian Bugs |
|---|---|---|---|---|---|---|
| fastnetmon | source | (unstable) | 1.2.9-1 | unimportant | 1138646 |
https://lorikeetsecurity.com/blog/fastnetmon-cve-2026-48690-packet-storage-integer-overflow
Crosses no real security boundary, requires attacker to modify config file
https://github.com/pavel-odintsov/fastnetmon/commit/4606af43731055297063177263c0107b82ef8986 (v1.2.9)
https://github.com/pavel-odintsov/fastnetmon/pull/1056