CVE-2021-26637

Unauthenticated remote device control

Published Jun 22, 2022 · Updated Aug 3, 2024

Improper authentication in SiHAS firmware and old app from Shina System allows remote attackers to control devices via network requests. Firmware and app interfaces perform no account authentication or permission checks before accepting commands for SGW-300, ACM-300 and GCM-300 devices. Any attacker able to reach the device service can issue control operations without credentials, affecting device confidentiality, integrity and availability.

CVSS severity9.8
Critical
EPSS probability1.87%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper authentication in SiHAS firmware and old app from Shina System allows remote attackers to control devices via network requests. Firmware and app interfaces perform no account authentication or permission checks before accepting commands for SGW-300, ACM-300 and GCM-300 devices. Any attacker able to reach the device service can issue control operations without credentials, affecting device confidentiality, integrity and availability.

The record

CVE
CVE-2021-26637
Published
Jun 22, 2022
Updated
Aug 3, 2024
Vendor
Shina System Co., Ltd.
Product
SiHAS firmware
Classifications
CWE-306, CWE-862, T1210
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 22, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record 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=1.xx

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Shina System Co., Ltd. · SiHAS firmwareversion=1.xx
Shina System Co., Ltd. · SiHAS old appversion=old app

Published CVSS scores

9.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
8.8KrCERT/CCCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/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)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-306Missing Authentication for Critical Function
CWE-862Missing Authorization
T1210Exploitation of Remote Services

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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