CVE-2025-20355 Overview
CVE-2025-20355 is an open redirect vulnerability in the web-based management interface of Cisco Catalyst Center Virtual Appliance. The flaw stems from improper input validation of HTTP request parameters. An unauthenticated, remote attacker can exploit the issue by intercepting and modifying an HTTP request from a legitimate user. Successful exploitation redirects the user to an attacker-controlled web page, enabling phishing and credential theft scenarios. The vulnerability is classified under CWE-601: URL Redirection to Untrusted Site.
Critical Impact
An unauthenticated remote attacker can redirect users of the Catalyst Center management interface to malicious sites, facilitating phishing attacks against network administrators.
Affected Products
- Cisco Catalyst Center Virtual Appliance (web-based management interface)
- Refer to the Cisco Security Advisory for the full list of affected versions
Discovery Timeline
- 2025-11-13 - CVE-2025-20355 published to the National Vulnerability Database
- 2026-06-17 - Last updated in the NVD database
Technical Details for CVE-2025-20355
Vulnerability Analysis
The vulnerability resides in the web-based management interface of Cisco Catalyst Center Virtual Appliance. The application accepts an HTTP request parameter that controls the destination of a client-side redirect. Because the interface fails to validate or restrict the redirect target against an allowlist of trusted domains, an attacker can supply an arbitrary external URL.
User interaction is required for exploitation. A victim must click a crafted link or submit an intercepted request. The attack works across privilege boundaries, so no authentication is needed to weaponize the flaw. Because Catalyst Center administers enterprise network infrastructure, the target audience consists of privileged network operators, making phishing lures highly effective.
Root Cause
The root cause is improper input validation on an HTTP request parameter that drives redirection logic. The interface uses attacker-controlled input as a redirect target without enforcing a domain allowlist, scheme restriction, or relative-path enforcement. This maps directly to CWE-601.
Attack Vector
The attack vector is network-based and requires user interaction. An attacker crafts a URL to the legitimate Catalyst Center management interface that includes a manipulated redirect parameter pointing to an attacker-controlled domain. When an administrator follows the link, the trusted interface issues a redirect to the malicious page. Because the initial hostname belongs to the legitimate appliance, users and security controls are more likely to trust the request. Attackers typically pair this with phishing pages that mimic Cisco or corporate single sign-on portals to harvest credentials or deliver malware.
No public proof-of-concept or exploit code has been observed. The vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog.
Detection Methods for CVE-2025-20355
Indicators of Compromise
- HTTP requests to the Catalyst Center management interface containing redirect parameters with absolute external URLs
- Web proxy or firewall logs showing HTTP 302 responses from the Catalyst Center hostname pointing to unrelated external domains
- Referrer headers on suspicious phishing pages that identify the Catalyst Center appliance as the origin
Detection Strategies
- Inspect access logs on the Catalyst Center Virtual Appliance for query strings containing URL-encoded external hostnames in redirect parameters
- Correlate administrator email or chat activity with URLs that reference the Catalyst Center interface but embed atypical redirect targets
- Deploy URL filtering rules that flag outbound redirects from internal management interfaces to external destinations
Monitoring Recommendations
- Forward Catalyst Center web server logs to a centralized SIEM or data lake for parameter-level inspection
- Alert on newly registered look-alike domains that could be used in redirect phishing campaigns
- Monitor authentication systems for anomalous administrator sign-in attempts following delivery of suspicious links
How to Mitigate CVE-2025-20355
Immediate Actions Required
- Review the Cisco Security Advisory and apply the fixed software release for Catalyst Center Virtual Appliance
- Restrict access to the Catalyst Center management interface to trusted administrative networks and jump hosts
- Educate network administrators about phishing links that reference legitimate Cisco management URLs
Patch Information
Cisco has published guidance and fixed software information in advisory cisco-sa-catc-open-redirect-3W5Bk3Je. Administrators should upgrade Catalyst Center Virtual Appliance to a release that includes the fix for CVE-2025-20355, as identified in the Cisco Security Advisory.
Workarounds
- No vendor-supplied workaround is documented; apply the patch as the primary remediation
- Enforce web proxy or URL filtering policies that block redirects from internal management URLs to unclassified external domains
- Require multi-factor authentication on all administrator accounts to reduce impact of credential phishing that leverages this redirect
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
