DEBIAN-CVE-2026-93424: Use After Free

FastNetMon is a high-performance DDoS detector and sensor. In version 1.2.9 and earlier, peerfindtemplate() in src/netflowplugin/netflowcollector.cpp and src/netflowplugin/netflowv9collector.cpp returns a pointer into globalnetflow9templates after releasing the cache mutex. On deployments with at least two entries in netflowports, concurrent template redefinition and data-flowset processing can let addupdatepeertemplate() reassign the template and free its records vector while another listener dereferences the escaped pointer. An unauthenticated sender that can reach both NetFlow/IPFIX listener ports can trigger a heap-use-after-free and reliably crash FastNetMon. No fixed release is available as of this review.