CVE-2025-20193: Cisco IOS XE Information Disclosure Flaw

CVE-2025-20193 Overview

CVE-2025-20193 is an input validation vulnerability in the web-based management interface of Cisco IOS XE Software. An authenticated, low-privileged, remote attacker can send crafted input to the web UI and read arbitrary files from the underlying operating system. The flaw is tracked under [CWE-78] (OS Command Injection) and is addressed in Cisco advisory cisco-sa-webui-multi-ARNHM4v6. Cisco IOS XE powers a wide range of enterprise routers, switches, and wireless controllers, which broadens the potential exposure to network operators.

Critical Impact
A low-privileged Web UI account can be leveraged to read sensitive files from the IOS XE host operating system, exposing configuration data, credentials, and cryptographic material.

Affected Products

Cisco IOS XE Software 17.3.x releases (17.3.1 through 17.3.8a)
Cisco IOS XE Software 17.4.x through 17.9.x releases with the Web UI enabled
Cisco IOS XE Software 17.10.x through 17.14.x releases (up to 17.14.1a)

Discovery Timeline

2025-05-07 - CVE-2025-20193 published to the National Vulnerability Database
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-20193

Vulnerability Analysis

The vulnerability resides in the web-based management interface exposed by Cisco IOS XE. The interface accepts user-supplied input but fails to sufficiently validate or sanitize it before passing it to operating system routines. An authenticated attacker with even minimal Web UI privileges can craft input that is interpreted by the underlying OS layer, resulting in disclosure of files that the Web UI process can access. Confidentiality is impacted, while integrity and availability of the device remain unaffected according to the published vector.

Root Cause

The root cause is insufficient input validation in Web UI handlers, classified under [CWE-78] (Improper Neutralization of Special Elements used in an OS Command). User-controlled parameters flow into a system call context without proper escaping or allow-list filtering. This allows attacker-controlled fragments to influence how the underlying command reads local resources, enabling arbitrary file read from the IOS XE Linux-based host.

Attack Vector

Exploitation requires network reachability to the Web UI and valid credentials for a low-privileged account. The attacker sends a crafted HTTP request to a vulnerable Web UI endpoint. The malformed input is processed by the backend, and the response returns the contents of files from the underlying OS. No user interaction is required and the attack complexity is low. Deployments that expose the Web UI to management VLANs or, worse, to untrusted networks are at highest risk.

No public proof-of-concept code is available for this issue. Refer to the Cisco Security Advisory for vendor technical details.

Detection Methods for CVE-2025-20193

Indicators of Compromise

Unexpected HTTP or HTTPS requests to Web UI endpoints from low-privileged accounts containing shell metacharacters such as ;, |, backticks, or $() sequences.
Web UI access logs showing repeated parameter fuzzing or requests referencing absolute paths like /etc/, /bootflash/, or /tmp/.
Successful authentications by service or read-only accounts followed by anomalous file-oriented API calls.

Detection Strategies

Inspect nginx and Web UI access logs on IOS XE devices for crafted parameters and correlate with the source user identity.
Deploy network intrusion detection signatures that flag OS command metacharacters in Web UI query strings and POST bodies.
Baseline normal administrative activity and alert on Web UI sessions that deviate from expected users, source IPs, or times of day.

Monitoring Recommendations

Forward IOS XE syslog, AAA, and Web UI logs to a centralized SIEM or data lake for correlation with authentication events.
Monitor outbound file transfers and configuration exports initiated shortly after Web UI authentication events.
Track privileged file access patterns and alert when low-privileged Web UI accounts trigger reads of sensitive configuration paths.

How to Mitigate CVE-2025-20193

Immediate Actions Required

Apply the fixed Cisco IOS XE release identified in advisory cisco-sa-webui-multi-ARNHM4v6 for your platform train.
Restrict Web UI access to trusted management networks using infrastructure access control lists and management VRFs.
Audit local Web UI accounts and remove or disable low-privileged users that are not strictly required.
Rotate credentials, keys, and shared secrets stored on the device if compromise is suspected.

Patch Information

Cisco has published fixed software releases in the Cisco Security Advisory cisco-sa-webui-multi-ARNHM4v6. Administrators should consult the advisory's Fixed Software section to select the appropriate upgrade path for their IOS XE train, including 17.3.x, 17.6.x, 17.9.x, 17.12.x, and 17.14.x deployments listed as affected.

Workarounds

Disable the HTTP and HTTPS server on the device when the Web UI is not required by running no ip http server and no ip http secure-server in global configuration.
Enforce role-based access control so that only high-privilege administrators can authenticate to the Web UI.
Place the management interface behind a jump host or bastion, and require multi-factor authentication for administrative access.

bash

# Configuration example: disable Web UI when not needed
configure terminal
 no ip http server
 no ip http secure-server
end
write memory