A malicious actor with access to the adjacent network could overflow the UniFi Protect Application (Version 6.1.79 and earlier) discovery protocol causing it to restart.
Affected Products:
UniFi Protect Application (Version 6.1.79 and earlier).
Mitigation:
Update your UniFi Protect Application to Version 6.2.72 or later.
Conclusion & alert: CVE-2026-21634 is rated Low Risk (26.9/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.02%).Mandatory action: Monitor for updates and reassess as exploit intelligence or EPSS changes.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
Exploit prediction scoring system (EPSS) score for CVE-2026-21634
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).