DEBIAN-CVE-2026-92698: Debian/fastnetmon vulnerability

FastNetMon is a high-performance DDoS detector and sensor. In version 1.2.9 and earlier, processsflowflowsample() in src/sflowplugin/sflowcollector.cpp passes the attacker-controlled sflowrawprotocolheadert.headersize to parserawpackettosimplepacketfull() as its trusted captured length without comparing it with the bytes remaining in the record. An inflated headersize creates a false end pointer beyond the received sFlow v5 UDP buffer, defeating the nested parser's bounds checks and causing an unauthenticated remote out-of-bounds read and process crash, with possible limited exposure of adjacent bytes through parsed flow fields. No fixed release is available as of this review.