CVE-2021-37183

Managed-device interruption via unauthenticated sleep notifications

Published Sep 14, 2021 · Updated Apr 23, 2025

Improper access control in Siemens SINEMA Remote Connect Server before 3.0 SP2 allows remote attackers to interrupt managed devices. The notification path permits send-to-sleep requests without authenticating or authorizing the sender. The attacker must be on the same network as the server; successful requests put managed devices to sleep and interrupt their availability.

CVSS severity6.5
Medium
EPSS probability0.37%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper access control in Siemens SINEMA Remote Connect Server before 3.0 SP2 allows remote attackers to interrupt managed devices. The notification path permits send-to-sleep requests without authenticating or authorizing the sender. The attacker must be on the same network as the server; successful requests put managed devices to sleep and interrupt their availability.

The record

CVE
CVE-2021-37183
Published
Sep 14, 2021
Updated
Apr 23, 2025
Vendor
Siemens
Product
SINEMA Remote Connect Server
Classifications
CWE-284, T1499
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 14, 2021CVE publishedPublication date reported by the CVE source.
  2. Apr 23, 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=All versions < V3.0 SP2

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Siemens · SINEMA Remote Connect Serverversion=All versions < V3.0 SP2

Published CVSS scores

3.3NIST NVDAV:A/AC:L/Au:N/C:N/I:N/A:P
6.5CISA ADP VulnrichmentCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.4SiemensCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H/E:P/RL:O/RC:C

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-284Improper Access Control
T1499Endpoint Denial 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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