How severe is CVE-2021-26637?

CVE-2021-26637 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over an adjacent network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-26637 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (75th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-26637?

CVE-2021-26637 primarily affects Shinasys Sihas Sgw-300 Firmware. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-26637?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-26637 published?

CVE-2021-26637 was published on 2022-06-23 and last updated on 2026-06-17.

CVE-2021-26637

CVE-2021-26637 is a high-severity vulnerability in Shinasys Sihas Sgw-300 Firmware with a CVSS 3.x base score of 8.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-306.

Key facts

Severity: High (CVSS 3.x base score 8.8)
CVSS v2: 7.5
EPSS exploit prediction: 2% (75th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-306
Affected product: Shinasys Sihas Sgw-300 Firmware
Published: 2022-06-23
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2021-26637?: 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.
How severe is CVE-2021-26637?: CVE-2021-26637 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over an adjacent network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-26637 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (75th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-26637?: CVE-2021-26637 primarily affects Shinasys Sihas Sgw-300 Firmware. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-26637?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-26637 published?: CVE-2021-26637 was published on 2022-06-23 and last updated on 2026-06-17.

References

https://www.krcert.or.kr/krcert/secNoticeView.do?bulletin_writing_sequence=66782

Affected products (6)

cpe:2.3:o:shinasys:sihas_sgw-300_firmware:-:*:*:*:*:android:*:*
cpe:2.3:o:shinasys:sihas_sgw-300_firmware:-:*:*:*:*:iphone_os:*:*
cpe:2.3:o:shinasys:sihas_acm-300_firmware:-:*:*:*:*:android:*:*
cpe:2.3:o:shinasys:sihas_acm-300_firmware:-:*:*:*:*:iphone_os:*:*
cpe:2.3:o:shinasys:sihas_gcm-300_firmware:-:*:*:*:*:android:*:*
cpe:2.3:o:shinasys:sihas_gcm-300_firmware:-:*:*:*:*:iphone_os:*:*

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