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CVE-2026-92698

8.2 highEPSS 0.3%

High (8.2) in pavel-odintsov fastnetmon. EPSS 0.3% estimated probability of exploitation activity in the next 30 days.

On this page
FastNetMon is a high-performance DDoS detector and sensor. In version 1.2.9 and earlier, process_sflow_flow_sample() in src/sflow_plugin/sflow_collector.cpp passes the attacker-controlled sflow_raw_protocol_header_t.header_size to parse_raw_packet_to_simple_packet_full() as its trusted captured length without comparing it with the bytes remaining in the record. An inflated header_size creates a false end pointer beyond the received sFlow v5 UDP buffer, defeating the nested parser's bounds checks and causing an unauthenticated remote out-of-bounds read and process crash, with possible limited exposure of adjacent bytes through parsed flow fields. No fixed release is available as of this review.

Severity

CVSS 3.1

8.2 high
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H
EPSS
0.3% estimated probability of exploitation activity in the next 30 days; 26th percentile. Scored 2026-11-10. A forecast for this CVE across the internet, not for your own systems.
CISA's assessment (SSVC)
Exploitation: none · Automatable: yes · Technical impact: partial, assessed 2026-11-09. From CISA's Vulnrichment in the CVE List: whether it is exploited, whether exploiting it can be automated, and how much control it gives.
CWE
CWE-125 Out-of-bounds Read
Published
Modified
NVD analysis
Deferred: the NVD does not plan to analyze it
Record from
the NVD, synced

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Affected

Versions

From the CNA's record in the CVE List.

ProductAffected
pavel-odintsov fastnetmon<= 1.2.9

Linux distributions

DistributionReleasePackageFixed inAdvisory
Debian12, 13, 14fastnetmonno fix listedDEBIAN-CVE-2026-92698
Ubuntu18.04:LTS, 26.10, Pro:20.04:LTS and 2 morefastnetmonno fix listedUBUNTU-CVE-2026-92698

From the distributions' data via OSV.dev: the Debian Security Tracker; Ubuntu Security Notices © Canonical Ltd., CC BY-SA 4.0. Modified: reformatted and linked to CVE records. Credits. On the distributions' own pages: Debian · Ubuntu.

Red Hat

Red Hat rates this Important.

Red Hat's statement

Red Hat Product Security rates this vulnerability as Important severity because an unauthenticated remote attacker can trigger a denial of service or disclose adjacent process memory without requiring prior privileges or user interaction. Successful exploitation causes FastNetMon to terminate abnormally, disrupting real-time network anomaly detection and DDoS monitoring across the infrastructure. This flaw specifically affects deployments where the sFlow collector plugin is enabled and reachable from untrusted network segments.

Red Hat's mitigation

To mitigate this issue, restrict network exposure of the sFlow collector port (default UDP port 6343) or disable the sFlow plugin if it is not required:

1. Restrict incoming sFlow traffic to trusted network flow exporter IP addresses using firewalld:

```

firewall-cmd --permanent --zone=public --remove-port=6343/udp

firewall-cmd --permanent --add-rich-rule='rule family="ipv4" source address="<TRUSTED_EXPORTER_IP>" port port="6343" protocol="udp" accept'

firewall-cmd --reload

```

2. Alternatively, if sFlow collection is not utilized by your deployment (e.g., using NetFlow or raw packet capture), disable sFlow processing in `/etc/fastnetmon.conf`:

```

sflow = off

```

After editing the configuration, restart the daemon:

```

systemctl restart fastnetmon

```

Warning: Restarting FastNetMon or reloading the firewall will briefly interrupt flow metrics collection and traffic monitoring. Disabling sFlow will halt all ingestion of sFlow telemetry.

Contains Red Hat Security Data © Red Hat, Inc., licensed under CC BY 4.0. Source: https://access.redhat.com/security/data. Modified: reformatted. Red Hat's page for CVE-2026-92698.

Attack patterns (CAPEC)

  • CAPEC-540 Overread Buffers Likelihood: Low · Severity: High

The attack patterns MITRE's CAPEC relates to this record's weaknesses, as MITRE names them. Credits.

References

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