CVE-2025-20236
📋 TL;DR
A vulnerability in Cisco Webex App's URL parser allows unauthenticated remote attackers to trick users into downloading malicious files via crafted meeting invite links. This could lead to arbitrary command execution on the user's system with their privileges. All users running vulnerable versions of Cisco Webex App are affected.
💻 Affected Systems
- Cisco Webex App
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with attacker gaining complete control over the user's device, data theft, lateral movement, and persistent access.
Likely Case
Malware installation leading to data exfiltration, ransomware deployment, or credential harvesting from the compromised system.
If Mitigated
Limited impact with user awareness preventing link clicks, endpoint protection blocking malicious downloads, or network filtering blocking exploit attempts.
🎯 Exploit Status
Exploitation requires social engineering but is technically simple once a user clicks the link.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Cisco advisory for specific fixed versions
Vendor Advisory: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-webex-app-client-rce-ufyMMYLC
Restart Required: Yes
Instructions:
1. Open Cisco Webex App. 2. Go to Help > Check for Updates. 3. Install available updates. 4. Restart the application.
🔧 Temporary Workarounds
Disable automatic URL handling
allConfigure Webex not to automatically process meeting links
Network filtering
allBlock suspicious meeting invite URLs at firewall/proxy
🧯 If You Can't Patch
- Implement strict endpoint protection with file download scanning
- Train users to avoid clicking unsolicited meeting links
🔍 How to Verify
Check if Vulnerable:
Check Webex App version against Cisco advisory; versions prior to fixed release are vulnerable.Check Version:
In Webex App: Help > About WebexVerify Fix Applied:
Confirm Webex App version matches or exceeds the patched version listed in Cisco advisory.📡 Detection & Monitoring
Log Indicators:
- Unusual file downloads triggered by Webex
- Process execution from unexpected Webex-related paths
Network Indicators:
- Outbound connections from Webex to unusual domains
- Downloads of executable files via Webex
SIEM Query:
source="webex" AND (event="file_download" OR event="process_execution")