Authentication Bypass by Spoofing in Cisco Identity Services Engine (ISE) - CVE-2026-20071
Published: September 18, 2026
Vulnerability identifier: #VU150833
CSH Severity: Medium
CVSS v4: 4.8 [CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N]
CVE-ID: CVE-2026-20071
CWE-ID: CWE-290
Exploitation vector: Adjecent network
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to bypass authentication process.
The vulnerability exists due to insufficient authentication checks that are performed while a user is being onboarded. A remote attacker on the local network can spoof the legitimate user and trigger a redirection to the guest web portal and gain access to the protected 802.1X network.
Affected software
Cisco Identity Services Engine (ISE)
How to mitigate CVE-2026-20071
Install updates from vendor's website.
Cisco Identity Services Engine (ISE) - addressed in versions 3.3 Patch 12, 3.4.0.608-Patch7, 3.5.0.527-Patch4