What’s Vulnerable › Vulnerabilities
CVE-2025-8679: ExtremeGuest Essentials Captive Portal Unauthenticated Brute Force
- Severity: critical (CVSS 9.8 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.3% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2025-10-01 · updated 2026-10-12
- Weakness: CWE-307
Description
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
- Extreme Networks ExtremeGuest Essentials: before 25.5.0 — fixed in 25.5.0
How to fix
Upgrade to a fixed version: Extreme Networks ExtremeGuest Essentials 25.5.0. Check the vendor advisory for mitigations.
References
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