Critical Remote Code Execution Vulnerability in Cisco Webex App
Cisco has disclosed a critical vulnerability tracked as CVE-2025-20236, affecting its popular Webex video conferencing platform. This flaw allows attackers to execute code remotely on a user’s machine. All they need to do is trick someone into clicking a specially crafted meeting link. The vulnerability lies in how the Webex App processes these custom URL links, allowing malicious instructions to bypass normal security checks. Cisco has since issued a fix and is strongly urging users to update immediately.
Although no active exploitation has been reported publicly, the ease of exploitation and the popularity of Webex among businesses and government organizations make this vulnerability particularly dangerous.
Technical Description
CVE-2025-20236 stems from improper input validation in how the Webex App interprets its custom meeting URLs. Webex apps use a proprietary URL scheme (like webex://) that allows users to launch or join meetings directly from their browser or email. However, attackers discovered they could embed malicious commands into these links because the app failed to sanitize the input properly.
When a victim clicks on one of these malicious Webex links, the application interprets hidden parameters in the URL that tell it to download and run arbitrary files all without proper verification. Because the app runs with the same permissions as the user, this gives the attacker the ability to install malware, exfiltrate data, or take full control of the system, depending on the payload used.
The exploit can be delivered through simple means like email, social media, or messaging apps no authentication or login credentials are required for it to work. The moment a victim clicks, the damage is done.
This issue is particularly concerning because it affects one of the most widely used video conferencing tools in the enterprise sector, where sensitive meetings, documents, and credentials are frequently shared.
Impact
The impact of CVE-2025-20236 is potentially severe. Exploiting this flaw gives an attacker the ability to execute arbitrary code on the victim’s machine. While they will not automatically gain admin privileges, they can still access personal files, install malware, or silently spy on users all through a simple meeting invite link.
This can be especially dangerous in enterprise or government environments, where a compromised endpoint can become an entry point for a broader network breach. For high-profile targets, attackers could use this to move laterally through systems or even install backdoors for future access.
Affected Versions:
- Cisco Webex App 44.6: all versions prior to 44.6.2.30589
- Cisco Webex App 44.7: all versions
- Versions 44.5 and earlier, as well as 44.8 and later, are NOT impacted.
IOC and Context Details
| Topics | Details |
|---|---|
| Tactic Name | Initial Access, Execution |
| Technique Name | Exploit Public-Facing Application |
| Sub Technique Name | Abuse of Custom URI Handlers |
| Attack Type | Remote Code Execution (RCE) via Malicious URL |
| Targeted Applications | Cisco Webex App (version 44.6, 44.7) |
| Region Impacted | Global |
| Industry Impacted | All |
| IOC’s | Malicious Webex meeting URLs (e.g., webex://...) |
| CVE | CVE-2025-20236 |
Recommended Actions
Cisco has already released patches for all affected versions, please update immediately:
- If you are using Webex App 44.6, update to 6.2.30589 or later
- If you are using version 44.7, upgrade to the fixed version or better yet, move to 8+