CVE-2025-20190: Cisco IOS XE Auth Bypass Vulnerability

CVE-2025-20190 Overview

CVE-2025-20190 is an access control vulnerability in the lobby ambassador web interface of Cisco IOS XE Wireless Controller Software. The flaw allows an authenticated remote attacker holding lobby ambassador credentials to delete arbitrary user accounts, including administrative accounts, on an affected device. Exploitation requires a valid lobby ambassador account, which is not configured by default. The weakness is classified under [CWE-284: Improper Access Control].

Critical Impact
A lobby ambassador account holder can send crafted HTTP requests to the management API and remove any user on the wireless controller, including administrators, resulting in loss of legitimate access and disruption of wireless management operations.

Affected Products

Cisco IOS XE Wireless Controller Software (releases including 17.6.8, 17.9.6, 17.9.6a, 17.12.1z2, 17.12.1z3, 17.15.1, 17.15.1x)
Cisco Catalyst 9800 Series Wireless Controllers (9800-40, 9800-80, 9800-L, CW9800H1, CW9800H2, CW9800M)
Cisco Catalyst 9800-CL Wireless Controllers for Cloud and Catalyst 9100 Series access points (9105AXI, 9115AXE/AXI, 9117AXI, 9120AXE/AXI/AXP, 9130AXE/AXI)

Discovery Timeline

2025-05-07 - CVE-2025-20190 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-20190

Vulnerability Analysis

The lobby ambassador role in Cisco IOS XE Wireless Controller Software is intended for limited guest-user administration, such as creating and managing temporary wireless guest accounts. The web interface backing this role exposes API endpoints that fail to enforce role-appropriate authorization on user-deletion actions. As a result, a lobby ambassador can invoke user management APIs reserved for higher-privileged administrators.

Successful exploitation removes user accounts from the running configuration. When an administrator account is deleted, legitimate operators lose management access to the wireless controller, forcing recovery through console or credential-reset procedures. Confidentiality is not affected, but integrity of the user database is compromised.

Root Cause

The root cause is insufficient access control checks on actions performed through the lobby ambassador web interface. The API validates that the caller is authenticated but does not confirm that the caller's role is authorized to perform user-deletion operations. This is a classic missing authorization defect aligned to [CWE-284].

Attack Vector

The attacker authenticates to the affected controller with a valid lobby ambassador account over the network, then submits crafted HTTP requests to the user management API. The requests target account-deletion endpoints normally restricted to administrators. Because credentials for the non-default lobby ambassador role are required, the vulnerability is not exploitable by anonymous attackers. Compromise of a lobby ambassador password, whether by phishing, reuse, or brute force, is sufficient to enable the attack. No verified public exploit or proof-of-concept is available.

Detection Methods for CVE-2025-20190

Indicators of Compromise

Unexpected user-account deletion events in the wireless controller's AAA or configuration logs, particularly for accounts with administrative privileges.
HTTP requests to user management API endpoints originating from sessions authenticated as a lobby ambassador rather than an administrator.
Sudden loss of administrative login capability accompanied by successful lobby ambassador session activity.

Detection Strategies

Correlate lobby ambassador login events with subsequent user-management API calls; legitimate lobby ambassador workflows should not delete non-guest accounts.
Enable and forward Cisco IOS XE syslog and AAA accounting records to a centralized log platform, and alert on configuration changes affecting privilege 15 users.
Baseline expected API usage per role and flag deviations, especially DELETE-style operations on user objects invoked by non-administrative sessions.

Monitoring Recommendations

Ingest Catalyst 9800 controller logs, RADIUS/TACACS+ accounting, and NETCONF/RESTCONF audit records into a SIEM for cross-source correlation.
Continuously monitor for administrative account inventory changes and generate alerts when accounts are removed outside change-management windows.
Track authentication failures and successes on lobby ambassador accounts to detect credential brute forcing or reuse from unusual source addresses.

How to Mitigate CVE-2025-20190

Immediate Actions Required

Apply the fixed Cisco IOS XE Wireless Controller Software release listed in the Cisco Security Advisory.
Audit all configured lobby ambassador accounts and remove any that are not actively required.
Rotate passwords for remaining lobby ambassador accounts and enforce strong, unique credentials.
Restrict management-plane access to the wireless controller to trusted administrative networks only.

Patch Information

Cisco has published fixed software for affected Catalyst 9800 series controllers and the Catalyst 9800-CL cloud controller. Refer to the Cisco Security Advisory cisco-sa-ewlc-user-del-hQxMpUDj for the fixed release matrix corresponding to each affected train (17.6, 17.9, 17.12, 17.15).

Workarounds

If patching cannot be performed immediately, disable the lobby ambassador role or remove all lobby ambassador accounts until the fix is applied.
Enforce network-level ACLs restricting HTTPS management access to designated jump hosts to reduce exposure of the lobby ambassador interface.
Enable AAA command accounting and configuration-change alerts so that any unauthorized user deletion is detected and can be reversed quickly from backup configuration.

bash

# Configuration example: remove lobby ambassador users and restrict HTTPS management access
configure terminal
 no username <lobby_ambassador_name>
 ip http access-class <trusted_mgmt_acl>
 ip access-list standard <trusted_mgmt_acl>
  permit <mgmt_subnet> <wildcard>
  deny   any log
end
write memory