What is CVE-2025-8679?

CVE-2025-8679 is a critical-severity vulnerability in Extreme Networks Extremeguest Essentials, classified under Improper Restriction of Excessive Authentication Attempts. CVSS score: 9.8/10. Published 2025-10-01.

How severe is CVE-2025-8679?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Is CVE-2025-8679 known to be exploited?

1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Vulnerability in Extreme Networks Extremeguest Essentials

CVE-2025-8679

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.

EPSS: 0.003 (24.3th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Extreme Networks Extremeguest Essentials — versions 25.4.0
Extremenetworks Extremeguest_essentials

Weakness classification (CWE)

CWE-307 — Improper Restriction of Excessive Authentication Attempts

Public proof-of-concept exploits

fkie-cad/nvd-json-data-feeds

References

1c053176-eef3-4d6a-ae0b-24728c86587b (Vendor Advisory)

Frequently asked questions

What is CVE-2025-8679?: CVE-2025-8679 is a critical-severity vulnerability in Extreme Networks Extremeguest Essentials, classified under Improper Restriction of Excessive Authentication Attempts. CVSS score: 9.8/10. Published 2025-10-01.
How severe is CVE-2025-8679?: Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2025-8679 known to be exploited?: 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.