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OpenAdvisories
Medium · 6.5 CVE-2026-48684 EUVD-2026-31840GHSA-6jf7-3j4w-4v3m

FastNetMon Community Edition through 1.2.9 contains an out-of-bounds read in the NetFlow v9 options template parser. In process_netflow_v9_…

Published May 26, 2026 · Updated May 26, 2026 · Assigned by mitre

Description

FastNetMon Community Edition through 1.2.9 contains an out-of-bounds read in the NetFlow v9 options template parser. In process_netflow_v9_options_template() (src/netflow_plugin/netflow_v9_collector.cpp), the scope parsing loop (lines 224-229) iterates until scopes_offset reaches the attacker-controlled option_scope_length value, reading netflow9_template_flowset_record_t structures at each step. No bounds check validates that (zone_address + scopes_offset + sizeof(record)) stays within the flowset. The same issue affects the options field loop (lines 241-257) with option_length. Furthermore, option_scope_length is not validated to be a multiple of sizeof(netflow9_template_flowset_record_t), potentially causing misaligned reads. An attacker can trigger reads past the end of the UDP packet buffer.

Fixed in Linux distributions

Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.

ReleasePackageFixed inAdvisory
Debian 14 fastnetmon 1.2.9-1 —
Debian 13 fastnetmon 1.2.9-0+deb13u1 —
Debian 12 fastnetmon No fix yet —
ReleasePackageFixed inAdvisory
Ubuntu 26.10 fastnetmon No fix yet —
Ubuntu 25.10 fastnetmon No fix yet —
Ubuntu 18.04 LTS fastnetmon No fix yet —
Show 3 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
Ubuntu Pro 26.04 LTS fastnetmon No fix yet —
Ubuntu Pro 24.04 LTS fastnetmon No fix yet —
Ubuntu Pro 20.04 LTS fastnetmon No fix yet —

References