CVE-2026-48683 Details
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.
A memory safety vulnerability allowing out-of-bounds read has been identified in FastNetMon Community Edition versions through 1.2.9. This issue resides in the NetFlow v9 data flowset processor, specifically within the 'src/netflow_plugin/netflow_v9_collector.cpp' file. The vulnerability arises because the Data template branch iterates over flow records without proper bounds checking against the end of the packet. Exploitation of this flaw could lead to the parser reading arbitrary memory beyond the packet buffer, potentially leaking sensitive information or causing a crash.
Users are advised to firewall the NetFlow port 2055 to allow only recognized router IPs, bind the collector to a specific management interface instead of the default '0.0.0.0', and monitor for anomalous flow record values that could indicate exploitation.
Metrics
CVSS 4.0 Severity and Vector Strings:
VolerionCVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
Volerion
Assessed May 26, 2026CISA-ADP
Assessed May 26, 2026References to Advisories, Solutions, and Tools
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Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-125 | Out-of-bounds Read | CISA-ADP |
Affected Products
| Product | Versions |
|---|---|
| FastNetMon | <= 1.2.9 (semver) |
CPE
Remediation
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Change History
5 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jul 24, 2026 | CVE Translated | [email protected] |
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| May 26, 2026 | CVE Modified | CISA-ADP |
| May 26, 2026 | New CVE Received | [email protected] |