CVE-2026-48684 Details
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.
A vulnerability allowing out-of-bounds read has been identified in FastNetMon Community Edition versions through 1.2.9. The issue arises in the NetFlow v9 options template parser, specifically within the 'process_netflow_v9_options_template' function of the NetFlow plugin collector. The vulnerability is caused by the parser's scope processing loop, which iterates based on an attacker-controlled length value without proper bounds checking. This flaw allows reads to extend beyond the intended buffer, potentially leading to information disclosure or a crash. The same issue occurs in the options field loop, with unvalidated length values causing misaligned reads. Exploitation can be triggered by sending crafted NetFlow v9 options templates to the collector's default UDP port.
Until a fix is released, it is recommended to allowlist the NetFlow port at the firewall, bind the collector to a management interface instead of '0.0.0.0', run the daemon under 'systemd-restart' with 'Restart=on-failure', and drop NetFlow v9 entirely if it is not needed.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-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 |
|---|---|
| pavel-odintsov fastnetmon | <= 1.2.9 |
CPE
Remediation
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Change History
6 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 27, 2026 | Initial Analysis | [email protected] |
| May 26, 2026 | CVE Modified | CISA-ADP |
| May 26, 2026 | New CVE Received | [email protected] |