FASTNETMON · CVE-2026-92698 · Package
NO FIX YET · SEE WHAT TO DO
FastNetMon, a DDoS detector, mishandles a crafted sFlow v5 UDP packet whose inner header size is inflated, so its parser reads past the received buffer. An unauthenticated remote sender can crash the process and may read limited adjacent memory through parsed flow fields.
first public Jul 20, 2026 · 2 sources
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Teams running FastNetMon 1.2.9 or earlier with the sFlow collector enabled and reachable over UDP. Deployments that do not use sFlow ingestion, or that restrict sFlow UDP traffic to trusted exporters, are less exposed. The sources state no fixed release is available yet.
Not affected if sflow-disabled, udp-restricted
Who cares ddos-detection, fastnetmon, self-hosted, sflow
1.2.9 and earlier are affected.FastNetMon is a high-performance DDoS detector and sensor. In version 1.2.9 and earlier, process_sflow_flow_sample() in src/sflow_plugin/sflow_collector.cpp passes the attacker-controlled sflow_raw_protocol_header_t.header_size to parse_raw_packet_to_simple_packet_full() as its trusted captured length without comparing it with the bytes remaining in the record. An inflated header_size 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.
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