A critical vulnerability has been identified in multiple Intelbras router models, assigned CVE-2025-26063 with a CVSS score of 9.8. This flaw allows an unauthenticated attacker to gain complete control of an affected device by simply creating a Wi-Fi network with a specially crafted name. Successful exploitation could lead to network traffic interception, denial of service, or further attacks on the internal network.

This vulnerability is a command injection flaw within the function that processes the Extended Service Set Identifier (ESSID), or Wi-Fi network name. An unauthenticated attacker with access to the device's network creation interface can submit a crafted ESSID containing arbitrary system commands. The device's software fails to properly sanitize this input, causing it to execute the injected commands with the privileges of the system, leading to remote code execution and a full compromise of the router.

This vulnerability is rated as critical severity with a CVSS score of 9.8, reflecting the ease of exploitation and the maximum potential impact. An attacker who successfully exploits this flaw can gain complete administrative control over the network device. This could lead to severe business disruptions, including the theft of sensitive data by sniffing all network traffic, launching denial-of-service attacks that take down the network, using the compromised router as a pivot point to attack other critical systems within the organization, or incorporating the device into a botnet for larger-scale attacks. The risk to data confidentiality, integrity, and availability is exceptionally high.

Immediate Action: The primary remediation step is to update the firmware on all affected Intelbras devices to the latest version provided by the vendor, which addresses this vulnerability. After patching, it is crucial to monitor systems for any signs of prior exploitation and to review device access and system logs for any anomalous activity related to network creation.

Proactive Monitoring: Security teams should implement monitoring rules to detect exploitation attempts. This includes scrutinizing logs for events related to the creation of new Wi-Fi networks, specifically looking for ESSID names that are unusually long or contain shell metacharacters (e.g., ;, |, &, $(, `). Monitor network traffic for unexpected outbound connections from the routers to unknown IP addresses, which could indicate a successful compromise.

Compensating Controls: If immediate patching is not feasible, implement the following controls to reduce risk:

• Restrict access to the router's management interface to a limited set of trusted IP addresses.
• If the management interface is web-based, place it behind a Web Application Firewall (WAF) with rules designed to block command injection attempts in input fields.
• Disable any guest or public-facing features that allow for the creation of new networks without authentication.

Public Exploit Available: false

Given the critical severity (CVSS 9.8) and the ability for an unauthenticated attacker to achieve remote code execution, this vulnerability poses an immediate and significant threat to the organization. We strongly recommend that all affected Intelbras RX1500 and RX3000 devices be patched immediately. Due to the high likelihood of future exploitation, this remediation effort should be treated as a top priority. If patching cannot be performed immediately, the compensating controls listed above must be implemented without delay to mitigate the risk of a full network compromise.