Cisco IOx Vulnerabilities: Unauthenticated Log Injection & Admin XSS

Recent security findings have revealed serious vulnerabilities in Cisco IOx that could let attackers inject fake log entries without logging in and execute cross-site scripting (XSS) attacks on administrative interfaces. These flaws pose a real risk to network security, potentially allowing unauthorized users to access or manipulate sensitive data.

Cisco identified two critical issues in its IOx application hosting environment on IOS XE Software ,one that lets attackers tamper with logs and another that allows malicious scripts to run, putting administrators at risk.

The Vulnerabilities

Stored Cross-Site Scripting (XSS) – CVE-2026-20112 : XSS is a vulnerability where an attacker injects malicious code (usually JavaScript) into a web page. When other users view the page, the malicious code runs in their browser. This flaw Could let attackers steal sensitive info or manipulate the management interface.

CRLF Injection – CVE-2026-20113 :

CRLF stands for Carriage Return Line Feed basically the “Enter” key in logs. CRLF injection lets an attacker insert fake log entries or modify existing ones. This flaw can obscure real events or insert misleading log info, hiding malicious activity.

Non Affected Software :

Cisco has confirmed the following Cisco products that support Cisco IOx application hosting environment are not affected by this vulnerability:

• 800 Series Industrial Integrated Services Routers (ISRs)
• Catalyst 3650 Series Switches
• Catalyst 3850 Series Switches
• Catalyst 9100 Family of Access Points (COS-APs)
• CGR1000 Compute Modules
• IC3000 Industrial Compute Gateways
• IR510 WPAN Industrial Routers
• IOS Software
• NX-OS Software
• Cisco IOS XR Software.

Devices are affected only if:

• Running Cisco IOS XE with IOx manually configured (not default).\To check, run:
• To check, run:
• show run | include iox
• If the output contains a line with iox only, as shown in the preceding example, the device is affected by this vulnerability.

Cisco Software Checker is a tool that helps identify which Cisco security advisories affect a particular software release.

Recommendations

1. Update Your Systems: Ensure that your Cisco IOx devices are updated with the latest security patches released by Cisco. Regular updates are crucial for mitigating known vulnerabilities.
2. Implement Access Controls: Strengthen access controls to administrative interfaces. Ensure that only authorized personnel have access to sensitive configurations and logs.