# CVE-2026-93424: FastNetMon: NetFlow/IPFIX template cache returns unlocked pointers, causing heap-use-after-free on multi-port deployments

Status: published. Published: 2026-11-05. Updated: 2026-11-05.

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.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- pavel-odintsov / fastnetmon: <= 1.2.9 (affected). Source: CNA: GitHub_M

## Severity and prioritization

- CVSS 3.1: 7.5 (high); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H; source: CNA: GitHub_M

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-416

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/pavel-odintsov/fastnetmon/security/advisories/GHSA-ph88-95vc-x6gv (CNA: GitHub_M; x_refsource_CONFIRM)

- https://github.com/pavel-odintsov/fastnetmon/commit/a24e528d145b5371a7ab0bcdde23e4b4b99506e9 (CNA: GitHub_M; x_refsource_MISC)

## Provenance

- CNA: GitHub_M: https://www.cve.org/CVERecord?id=CVE-2026-93424; retrieved 2026-11-05; source updated 2026-11-05

Revision: d8216712485d6b7f5bd6212f245d56f2482140923fad6c10712f3412f4c94b86

Canonical: https://y2.dev/cve/CVE-2026-93424

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