---
id: CVE-2026-93424
title: >-
  FastNetMon: NetFlow/IPFIX template cache returns unlocked pointers, causing
  heap-use-after-free on multi-port deployments
summary: >-
  FastNetMon is a high-performance DDoS detector and sensor. In version 1.2.9
  and earlier, peer_find_template() in src/netflow_plugin/netflow_collector.cpp
  and src/netflow_plugin/netflow_v9_collector.cpp returns a pointer into
  global_netfl…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cvssSource: cna
cwe:
  - CWE-416
vendor: pavel-odintsov
product: fastnetmon
affected:
  - fastnetmon <= 1.2.9
published: '2026-11-05'
updated: '2026-11-05'
sourceUpdated: '2026-11-05T22:31:58.734Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-93424'
references:
  - url: >-
      https://github.com/pavel-odintsov/fastnetmon/security/advisories/GHSA-ph88-95vc-x6gv
    label: >-
      https://github.com/pavel-odintsov/fastnetmon/security/advisories/GHSA-ph88-95vc-x6gv
  - url: >-
      https://github.com/pavel-odintsov/fastnetmon/commit/a24e528d145b5371a7ab0bcdde23e4b4b99506e9
    label: >-
      https://github.com/pavel-odintsov/fastnetmon/commit/a24e528d145b5371a7ab0bcdde23e4b4b99506e9
tags:
  - cve.org
ingestedAt: '2026-11-05T23:41:31.943Z'
epss: 0.00278
epssPercentile: 0.20404
---

## Overview

FastNetMon is a high-performance DDoS detector and sensor. In version 1.2.9 and earlier, peer_find_template() in src/netflow_plugin/netflow_collector.cpp and src/netflow_plugin/netflow_v9_collector.cpp returns a pointer into global_netflow9_templates after releasing the cache mutex. On deployments with at least two entries in netflow_ports, concurrent template redefinition and data-flowset processing can let add_update_peer_template() reassign the template and free its records vector while another listener dereferences the escaped pointer. An unauthenticated sender that can reach both NetFlow/IPFIX listener ports can trigger a heap-use-after-free and reliably crash FastNetMon. No fixed release is available as of this review.

## Affected

- `fastnetmon <= 1.2.9`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.