CVE-2026-34021

Alarm deactivation via unauthenticated RS-485 message replay

Published Jun 15, 2026 · Updated Jun 15, 2026

Authentication bypass in Wertheim SafeController 5400 6.11.8130.22320 allows attackers to disable its safe alarm via RS-485 replay. The server-to-microcontroller serial channel lacks cryptographic protection, so the controller accepts replayed control messages as legitimate. Access to the serial traffic or a compromised server is required; replaying a captured “quit alarm” command can keep the alarm deactivated.

CVSS severity8.6
High
EPSS probability0.20%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in Wertheim SafeController 5400 6.11.8130.22320 allows attackers to disable its safe alarm via RS-485 replay. The server-to-microcontroller serial channel lacks cryptographic protection, so the controller accepts replayed control messages as legitimate. Access to the serial traffic or a compromised server is required; replaying a captured “quit alarm” command can keep the alarm deactivated.

The record

CVE
CVE-2026-34021
Published
Jun 15, 2026
Updated
Jun 15, 2026
Vendor
Wertheim Vertriebsgesellschaft m.b.H.
Product
Wertheim SafeController 5400
Classifications
CWE-294, T0838
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 15, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 15, 2026Record 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=Wertheim SafeController 5400, Controller 5400 - AssemblyVersion 6.11.8130.22320

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Wertheim Vertriebsgesellschaft m.b.H. · Wertheim SafeController 5400version=Wertheim SafeController 5400, Controller 5400 - AssemblyVersion 6.11.8130.22320

Published CVSS scores

8.6SEC Consult Vulnerability LabCVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

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)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-294Authentication Bypass by Capture-replay
T0838Modify Alarm Settings

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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