CVE-2021-27289
CRITICALDescription
A replay attack vulnerability was discovered in a Zigbee smart home kit manufactured by Ksix (Zigbee Gateway Module = v1.0.3, Door Sensor = v1.0.7, Motion Sensor = v1.0.12), where the Zigbee anti-replay mechanism - based on the frame counter field - is improperly implemented. As a result, an attacker within wireless range can resend captured packets with a higher sequence number, which the devices incorrectly accept as legitimate messages. This allows spoofed commands to be injected without authentication, triggering false alerts and misleading the user through notifications in the mobile application used to monitor the network.
How to fix
No published remediation has been found for this vulnerability's affected products yet.
Mitigation guidance may be in the linked vendor advisories in the References section below.
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CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
Exploit Intelligence
Moderate risk: more likely to be exploited than 54% of all known CVEs.
References
Related Vulnerabilities
Other CWE-294 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2023-23397 | Critical | 9.8 | 97% | KEV | Fix |
| CVE-2017-3191 | Critical | 9.8 | 63% | - | - |
| CVE-2023-49231 | Critical | 9.8 | 43% | - | - |
| CVE-2002-0054 | High | 7.5 | 22% | - | - |
| CVE-2022-29593 | Medium | 5.9 | 13% | - | - |
| CVE-2022-22806 | Critical | 9.8 | 12% | - | - |
Common questions
How do I fix CVE-2021-27289?
No published fix for CVE-2021-27289 has been found yet. Check the linked vendor advisories for guidance as it becomes available.
Is CVE-2021-27289 being actively exploited?
Not that we know of. CVE-2021-27289 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.82% is the estimated probability that it will be exploited in the next 30 days. That is higher than 54% of all scored CVEs.
How severe is CVE-2021-27289?
CVE-2021-27289 has a CVSS v3 base score of 9.1, rated critical. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-04-16.