CVE-2026-92694

MEDIUM 5.9

FastNetMon: IPv6 host counters map iterated without lock, racing concurrent inserts

CVSS Score

5.9

EPSS Score

0.0%

EPSS Percentile

0th

FastNetMon is a high-performance DDoS detector and sensor. In version 1.2.9 and earlier, FastNetMon's IPv6 top-talkers screen-draw thread in draw_table_ipv6() in src/fastnetmon_logic.cpp iterates ipv6_host_counters.average_speed_map without holding counter_map_mutex while recalculate_speed() inserts new keys and may rehash the same map. The race requires networks_list to include the targeted IPv6 range. It causes confirmed undefined behavior under load; a process crash is plausible but was not observed, so reliable denial of service has not been established. No fixed release is available as of this review.

CWE	CWE-362
Vendor	pavel-odintsov
Product	fastnetmon
Published	Nov 5, 2026

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CVSS v3 Breakdown

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

Attack Vector

Network

Attack Complexity

High

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Affected Versions

pavel-odintsov / fastnetmon

<= 1.2.9

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/pavel-odintsov/fastnetmon/security/advisories/GHSA-phrw-2q76-5m7h github.com: https://github.com/pavel-odintsov/fastnetmon/pull/1087 github.com: https://github.com/pavel-odintsov/fastnetmon/commit/1294724ea931dc78fe545360f2193398bba35381