CVE-2022-21155Network attack vector

Unauthenticated server crash via crafted packet

Published Apr 12, 2022 · Updated Apr 16, 2025

Denial of service in Fernhill SCADA Server 3.77 and earlier allows remote attackers to crash the server via a crafted packet. The listener on TCP port 20295 raises an exception while processing the packet, causing the FHSvrService.exe server process to exit. No authentication or user interaction is required, and the documented consequence is interruption of the SCADA server process.

CVSS severity7.5
High
EPSS probability1.12%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Fernhill SCADA Server 3.77 and earlier allows remote attackers to crash the server via a crafted packet. The listener on TCP port 20295 raises an exception while processing the packet, causing the FHSvrService.exe server process to exit. No authentication or user interaction is required, and the documented consequence is interruption of the SCADA server process.

The record

CVE
CVE-2022-21155
Published
Apr 12, 2022
Updated
Apr 16, 2025
Vendor
Fernhill Software
Product
Fernhill SCADA Server
Classifications
CWE-400, CWE-755, T0814
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 12, 2022CVE publishedPublication date reported by the CVE source.
  2. Apr 16, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified <=3.77

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Fernhill Software · Fernhill SCADA Serverversion=unspecified <=3.77

Published CVSS scores

7.5ICS-CERTCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5.0NIST NVDAV:N/AC:L/Au:N/C:N/I:N/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-400Uncontrolled Resource Consumption
CWE-755Improper Handling of Exceptional Conditions
T0814Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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