CVE-2021-27289
Published: 15 April 2025
Summary
CVE-2021-27289 is a critical-severity Authentication Bypass by Capture-replay (CWE-294) vulnerability. Its CVSS base score is 9.1 (Critical).
Operationally, ranked in the top 34.3% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2021-14054
Vulnerability details
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…
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- 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.
- CWE(s)
Related Threats
No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.
Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Allows detection of capture-replay attacks by showing the replayed logon's timestamp as the last logon.
Protects against replay of captured session tokens or credentials by requiring authenticated, fresh session channels.
Wireless link protections commonly incorporate replay protection, reducing the exploitability of capture-replay weaknesses.
Accurate synchronized time enables tight timestamp windows that directly limit capture-replay windows in authentication protocols.