CVE-2026-48683: FastNetMon Community Edition through 1.2.9 contains an out-of-bounds read vulnerability in the NetFlow v9 data flowset processor. In src/netflow_plugi...

Description

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.

Metrics

CVSS 3.1

6.5/10

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

EPSS Probability

0.33%

24.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-125

References

Timeline

Published: May 26, 2026
Last Modified: Jun 17, 2026
Status: Deferred

Frequently Asked Questions

What is CVE-2026-48683?

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.

How severe is CVE-2026-48683?

CVE-2026-48683 has a CVSS score of 6.5/10 (MEDIUM severity). The EPSS model estimates a 0.33% probability of exploitation in the next 30 days.

How do I fix CVE-2026-48683?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.