Vulnerability · Published Oct 1, 2025 · Assigned by ExtremeNetworks

CVE-2025-8679ExtremeGuest Essentials Captive Portal Unauthenticated Brute Force

High 7.6

In plain English

A high-severity security flaw in ExtremeGuest Essentials from Extreme Networks. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 28% of all known vulnerabilities).

Severity (CVSS 4.0)7.6High
Exploit odds (30 days)0.3%top 72.5% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official 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 (as reported)

VendorProductVersions
Extreme Networks ExtremeGuest Essentials 25.4.0

Weakness: CWE-307 · Vector: CVSS:4.0/AV:A/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

References