CVE-2022-31766Network attack vector

Remote device reboot via malformed TCP Event packets

Published Oct 11, 2022 · Updated Apr 21, 2025

Improper input validation in Siemens SCALANCE and RUGGEDCOM firmware allows remote attackers to reboot devices via TCP Event packets. The TCP Event service improperly processes malformed packets, causing the device to become unusable and reboot. The service must be enabled, is disabled by default, and listens on TCP port 26864; no authentication or user interaction is required.

CVSS severity8.6
High
EPSS probability1.14%
Next 30 days · Sep 17, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Improper input validation in Siemens SCALANCE and RUGGEDCOM firmware allows remote attackers to reboot devices via TCP Event packets. The TCP Event service improperly processes malformed packets, causing the device to become unusable and reboot. The service must be enabled, is disabled by default, and listens on TCP port 26864; no authentication or user interaction is required.

The record

CVE
CVE-2022-31766
Published
Oct 11, 2022
Updated
Apr 21, 2025
Vendor
Siemens
Product
SCALANCE MUM856-1 (RoW)
Classifications
CWE-20, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 11, 2022CVE publishedPublication date reported by the CVE source.
  2. Apr 21, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=0 <V7.1.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Siemens · SCALANCE MUM856-1 (RoW)version=0 <V7.1.2
Siemens · SCALANCE MUM856-1 (EU)version=0 <V7.1.2
Siemens · SCALANCE WAM766-1 (US)version=V1.1.0 <V3.0.0
Siemens · RUGGEDCOM RM1224 LTE(4G) NAMversion=0 <V7.1.2
Siemens · RUGGEDCOM RM1224 LTE(4G) EUversion=0 <V7.1.2
Siemens · SCALANCE WUM766-1version=V1.1.0 <V3.0.0
Siemens · SCALANCE M874-3version=0 <V7.1.2
Siemens · SCALANCE WAM763-1version=V1.1.0 <V3.0.0
Siemens · SCALANCE WAM766-1version=V1.1.0 <V3.0.0
Siemens · SCALANCE M812-1 ADSL Routerversion=0 <V7.1.2
Siemens · SCALANCE S615 EEC LAN Routerversion=0 <V7.1.2
Siemens · SCALANCE M826-2 SHDSL-Routerversion=0 <V7.1.2
Siemens · SCALANCE M816-1 ADSL Routerversion=0 <V7.1.2
Siemens · SCALANCE M876-3 (ROK)version=0 <V7.1.2
Siemens · SCALANCE M876-3version=0 <V7.1.2
Siemens · SCALANCE WAM766-1 EECversion=V1.1.0 <V3.0.0
Siemens · SCALANCE M804PBversion=0 <V7.1.2
Siemens · SCALANCE WAM766-1 EEC (US)version=V1.1.0 <V3.0.0
Siemens · SCALANCE M876-4version=0 <V7.1.2
Siemens · SCALANCE M876-4 (NAM)version=0 <V7.1.2
Siemens · SCALANCE MUM853-1 (EU)version=0 <V7.1.2
Siemens · SCALANCE WUM766-1 (USA)version=V1.1.0 <V3.0.0
Siemens · SCALANCE S615 LAN-Routerversion=0 <V7.1.2
Siemens · SCALANCE WUM763-1version=V1.1.0 <V3.0.0
Siemens · SCALANCE M876-4 (EU)version=0 <V7.1.2
Siemens · SCALANCE M874-2version=0 <V7.1.2

Published CVSS scores

8.6NISTCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
8.6Siemens AGCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-20Improper Input Validation
T1499.004Application or System Exploitation

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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo