CVE-2025-50989: OPNsense Command Injection Vulnerability

Overview

The cybersecurity ecosystem has recently observed a significant vulnerability CVE-2025-50989, affecting OPNsense 25.1 users. This vulnerability is of particular concern as it lies within an authenticated command injection in the Bridge Interface Edit endpoint (interfaces_bridge_edit.php). The vulnerability’s gravity is underscored by its potential to allow an administrator to inject arbitrary shell operators and payloads, which might lead to a full system compromise or data leakage.
This vulnerability is a stark reminder of the risks associated with inadequate input validation and improper handling of user-supplied data in backend command invocations. It brings to light the critical need for robust cybersecurity measures in our increasingly digital world, where every potential weak spot can be exploited by malicious actors.

Vulnerability Summary

CVE ID: CVE-2025-50989
Severity: High (CVSS: 8.8)
Attack Vector: Network
Privileges Required: Administrator
User Interaction: Required
Impact: Full system compromise or data leakage

Affected Products

Product | Affected Versions

OPNsense | 25.1

How the Exploit Works

The exploit takes advantage of an authenticated command injection vulnerability in the Bridge Interface Edit endpoint of OPNsense. The ‘span’ POST parameter is concatenated into a system-level command without adequate sanitation or escaping. This flaw allows an authenticated administrator to inject arbitrary shell operators and payloads. Successful exploitation of this vulnerability permits remote code execution with the privileges of the web service, typically root, which could potentially lead to a full system compromise or lateral movement.

Conceptual Example Code

Here’s a conceptual example of the HTTP request that might exploit this vulnerability:

POST /interfaces_bridge_edit.php HTTP/1.1
Host: target.example.com
Content-Type: application/x-www-form-urlencoded
Authorization: Basic base64encoded(username:password)
span=valid_bridge_span ; injected_shell_command ;

In the above example, “valid_bridge_span” is a legitimate input for the ‘span’ parameter, while “injected_shell_command” is the malicious payload. The separator ‘;’ allows the malicious command to be executed after the legitimate one.

Workarounds and Mitigation

OPNsense users are advised to apply the vendor patch as soon as it is available to fix this vulnerability. In the absence of a patch, the use of a Web Application Firewall (WAF) or Intrusion Detection System (IDS) can temporarily mitigate the risk. These systems can be configured to detect and block attempts to exploit this vulnerability. It’s also recommended to limit the number of users with administrator privileges and enforce a strong password policy to minimize the risk of exploitation.