CVE-2021-26637
SiHAS Improper Authentication vulnerability
There is no account authentication and permission check logic in the firmware and existing apps of SiHAS's SGW-300, ACM-300, GCM-300, so unauthorized users can remotely control the device.
Attack profile
How easy it is to exploit
- Attack vector
- Adjacent network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
SiHAS Improper Authentication vulnerability
There is no account authentication and permission check logic in the firmware and existing apps of SiHAS's SGW-300, ACM-300, GCM-300, so unauthorized users can remotely control the device.
- Record
CVE-2021-26637- CVSS 3.1
- 8.8 High
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-287
- Updated
- 2026-11-02
EUVDEUVD-2021-13431
There is no account authentication and permission check logic in the firmware and existing apps of SiHAS's SGW-300, ACM-300, GCM-300, so unauthorized users can remotely control the device.
- Record
EUVD-2021-13431- CVSS 3.1
- 8.8 High
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-4j8v-2qmr-6m8p
There is no account authentication and permission check logic in the firmware and existing apps...
There is no account authentication and permission check logic in the firmware and existing apps of SiHAS's SGW-300, ACM-300, GCM-300, so unauthorized users can remotely control the device.
- Record
GHSA-4j8v-2qmr-6m8p- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-287, CWE-306
- Updated
- 2026-11-02
NVD
There is no account authentication and permission check logic in the firmware and existing apps of SiHAS's SGW-300, ACM-300, GCM-300, so unauthorized users can remotely control the device.
- Record
CVE-2021-26637- CVSS 3.1
- 8.8 High
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - CVSS 2.0
- 7.5 High
AV:N/AC:L/Au:N/C:P/I:P/A:P - Weakness
- CWE-287, CWE-306, CWE-862
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-26637 is a high vulnerability (CVSS 8.8) in Shina System Co.,ltd Sihas Firmware, published June 22, 2022. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.92%, the 79th percentile. No source names a fixed version.