CVE-2025-8679: Extremenetworks Extremeguest Essentials

Critical severity, CVSS 9.8. EPSS: 0.3% chance of exploitation in the next 30 days.

In ExtremeGuest Essentials before 25.5.0, captive-portal may permit unauthorized access via manual brute-force procedure. Under certain ExtremeGuest Essentials captive-portal SSID configurations, repeated manual login attempts may allow an unauthenticated device to be marked as authenticated and obtain network access. Client360 logs may display the client MAC as the username despite no MAC-authentication being enabled.

Affected products

• Extremenetworks Extremeguest Essentials: before 25.5.0 (fixed in 25.5.0)

Published 2025-10-01. Last modified 2026-06-17.