CVE-2026-48683

fastnetmon: FastNetMon Community Edition through 1.2.9 contains an out-of-bounds read vulnerability in the NetFlow v9 data flowse...

CVE-2026-48683 is fixed in fastnetmon on 1 platform, first by DEBIAN-CVE-2026-48683, released June 24, 2026. It is not reported as exploited. Patch Radar priority: Routine.

Routine
CVSS
6.5
medium
Exploitation
None reported
No vendor assessment
CISA KEV
Not listed
Not in the Known Exploited Vulnerabilities catalog
EPSS
0.0033
26th percentile

FastNetMon Community Edition through 1.2.9 contains an out-of-bounds read vulnerability in the NetFlow v9 data flowset processor. In src/netflow_plugin/netflow_v9_collector.cpp, the Data template branch (lines 1695-1702) iterates over flow records without performing a per-iteration bounds check against the packet end pointer. In contrast, the Options template branch (lines 1709-1719) correctly checks 'if (pkt + offset + field_template->total_length > packet_end)' before each iteration. The Data branch omits this check entirely. Since template definitions are sent by the network peer (and are unauthenticated UDP), an attacker can craft templates that cause the parser to read arbitrary memory past the packet buffer. This can leak sensitive memory contents or cause a crash.

Where it's fixed

ProductFixed inFixReleased
Linux
fastnetmon · Debian 13.5 (trixie) 1.2.9-0+deb13u1 DEBIAN-CVE-2026-48683 Jun 24, 2026
fastnetmon · Debian 14 1.2.9-1 DEBIAN-CVE-2026-48683 Jun 24, 2026

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